<?xml version="1.0" encoding="UTF-8"?>

<!--XBRL Document Created with the Workiva Platform-->
<!--Copyright 2024 Workiva-->
<!--r:5f5368a7-633d-4f1a-8227-49cf825c26ab,g:8d0b9682-dd3e-4cdc-9cf9-093d0dbf096a-->
<link:linkbase xmlns:link="http://www.xbrl.org/2003/linkbase" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xbrldt="http://xbrl.org/2005/xbrldt" xsi:schemaLocation="http://www.xbrl.org/2003/linkbase http://www.xbrl.org/2003/xbrl-linkbase-2003-12-31.xsd">
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/all" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#all"/>
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#hypercube-dimension"/>
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#dimension-default"/>
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#dimension-domain"/>
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/domain-member" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#domain-member"/>
  <link:roleRef roleURI="http://honestco.com/role/CondensedConsolidatedStatementsofRedeemableConvertiblePreferredStockandStockholdersEquityDeficit" xlink:type="simple" xlink:href="hnst-20240630.xsd#CondensedConsolidatedStatementsofRedeemableConvertiblePreferredStockandStockholdersEquityDeficit"/>
  <link:definitionLink xlink:role="http://honestco.com/role/CondensedConsolidatedStatementsofRedeemableConvertiblePreferredStockandStockholdersEquityDeficit" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementLineItems_5d079814-1eb5-4733-8829-36e543916377" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_StatementLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementTable_363f1e33-a840-4d80-a1bc-a21925a2cd21" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_StatementTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_5d079814-1eb5-4733-8829-36e543916377" xlink:to="loc_us-gaap_StatementTable_363f1e33-a840-4d80-a1bc-a21925a2cd21" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementEquityComponentsAxis_bf3b5248-ad10-4008-a5b2-f1ffd549ba87" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_StatementEquityComponentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_363f1e33-a840-4d80-a1bc-a21925a2cd21" xlink:to="loc_us-gaap_StatementEquityComponentsAxis_bf3b5248-ad10-4008-a5b2-f1ffd549ba87" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_bf3b5248-ad10-4008-a5b2-f1ffd549ba87_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_bf3b5248-ad10-4008-a5b2-f1ffd549ba87" xlink:to="loc_us-gaap_EquityComponentDomain_bf3b5248-ad10-4008-a5b2-f1ffd549ba87_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_64840876-ff43-4a5e-a530-5996333615e9" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_bf3b5248-ad10-4008-a5b2-f1ffd549ba87" xlink:to="loc_us-gaap_EquityComponentDomain_64840876-ff43-4a5e-a530-5996333615e9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockMember_fa8c9e93-b291-4d82-bc6f-56d5ab91cdc0" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_CommonStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_64840876-ff43-4a5e-a530-5996333615e9" xlink:to="loc_us-gaap_CommonStockMember_fa8c9e93-b291-4d82-bc6f-56d5ab91cdc0" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdditionalPaidInCapitalMember_5f848256-e1b5-415a-839c-cee13b1c76da" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_AdditionalPaidInCapitalMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_64840876-ff43-4a5e-a530-5996333615e9" xlink:to="loc_us-gaap_AdditionalPaidInCapitalMember_5f848256-e1b5-415a-839c-cee13b1c76da" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetainedEarningsMember_8805fe23-ecae-40b5-b2bb-15d2dc5ab222" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_RetainedEarningsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_64840876-ff43-4a5e-a530-5996333615e9" xlink:to="loc_us-gaap_RetainedEarningsMember_8805fe23-ecae-40b5-b2bb-15d2dc5ab222" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_a23d3be5-a2b7-4b20-9eab-6c63f80a636e" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_64840876-ff43-4a5e-a530-5996333615e9" xlink:to="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_a23d3be5-a2b7-4b20-9eab-6c63f80a636e" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_dcce56c3-1855-4355-8c5a-64523688bbc5" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_IncreaseDecreaseInStockholdersEquityRollForward"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_5d079814-1eb5-4733-8829-36e543916377" xlink:to="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_dcce56c3-1855-4355-8c5a-64523688bbc5" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockSharesOutstanding_0d51035c-b8c3-43c3-963a-1347bc3c0693" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_CommonStockSharesOutstanding"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_dcce56c3-1855-4355-8c5a-64523688bbc5" xlink:to="loc_us-gaap_CommonStockSharesOutstanding_0d51035c-b8c3-43c3-963a-1347bc3c0693" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquity_349a3129-dd7f-4ad3-84a5-e46fc3af0365" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_StockholdersEquity"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_dcce56c3-1855-4355-8c5a-64523688bbc5" xlink:to="loc_us-gaap_StockholdersEquity_349a3129-dd7f-4ad3-84a5-e46fc3af0365" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLoss_ced4ad23-6053-4cf6-b5ec-e236fa557a4a" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_NetIncomeLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_dcce56c3-1855-4355-8c5a-64523688bbc5" xlink:to="loc_us-gaap_NetIncomeLoss_ced4ad23-6053-4cf6-b5ec-e236fa557a4a" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent_85f38751-3a8d-44c4-965b-f6aff274bf38" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_dcce56c3-1855-4355-8c5a-64523688bbc5" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent_85f38751-3a8d-44c4-965b-f6aff274bf38" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised_c8510ce2-6fd4-490a-9247-63294baefd9d" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_dcce56c3-1855-4355-8c5a-64523688bbc5" xlink:to="loc_us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised_c8510ce2-6fd4-490a-9247-63294baefd9d" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodValueStockOptionsExercised_611e7d34-7684-4055-a085-30099e8b18d1" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_StockIssuedDuringPeriodValueStockOptionsExercised"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_dcce56c3-1855-4355-8c5a-64523688bbc5" xlink:to="loc_us-gaap_StockIssuedDuringPeriodValueStockOptionsExercised_611e7d34-7684-4055-a085-30099e8b18d1" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue_b9d0120f-b6b0-4057-81c4-b89c8be9af7e" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_dcce56c3-1855-4355-8c5a-64523688bbc5" xlink:to="loc_us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue_b9d0120f-b6b0-4057-81c4-b89c8be9af7e" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodSharesRestrictedStockAwardNetOfForfeitures_91d98d81-b965-4ce5-8f6d-ebb0966e58ec" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_StockIssuedDuringPeriodSharesRestrictedStockAwardNetOfForfeitures"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_dcce56c3-1855-4355-8c5a-64523688bbc5" xlink:to="loc_us-gaap_StockIssuedDuringPeriodSharesRestrictedStockAwardNetOfForfeitures_91d98d81-b965-4ce5-8f6d-ebb0966e58ec" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodSharesEmployeeStockPurchasePlans_ed018dea-21f4-481d-a0ce-be16e5dcc28c" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_StockIssuedDuringPeriodSharesEmployeeStockPurchasePlans"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_dcce56c3-1855-4355-8c5a-64523688bbc5" xlink:to="loc_us-gaap_StockIssuedDuringPeriodSharesEmployeeStockPurchasePlans_ed018dea-21f4-481d-a0ce-be16e5dcc28c" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodValueEmployeeStockPurchasePlan_74ebe1b6-6a78-49cb-9901-cd61af0ea4c8" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_StockIssuedDuringPeriodValueEmployeeStockPurchasePlan"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_dcce56c3-1855-4355-8c5a-64523688bbc5" xlink:to="loc_us-gaap_StockIssuedDuringPeriodValueEmployeeStockPurchasePlan_74ebe1b6-6a78-49cb-9901-cd61af0ea4c8" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockSharesOutstanding_a279a0aa-cdec-4880-90ca-f5e3eaae462f" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_CommonStockSharesOutstanding"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquity_4ac33b0d-eb7c-4498-bf6d-217835397929" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_StockholdersEquity"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://honestco.com/role/RevenueDetails" xlink:type="simple" xlink:href="hnst-20240630.xsd#RevenueDetails"/>
  <link:definitionLink xlink:role="http://honestco.com/role/RevenueDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisaggregationOfRevenueLineItems_4a008967-853e-4ad3-8b4e-092b8f3c9982" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DisaggregationOfRevenueLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisaggregationOfRevenueTable_6af2b21e-db6b-411c-940c-09b6fe5d6c54" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DisaggregationOfRevenueTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DisaggregationOfRevenueLineItems_4a008967-853e-4ad3-8b4e-092b8f3c9982" xlink:to="loc_us-gaap_DisaggregationOfRevenueTable_6af2b21e-db6b-411c-940c-09b6fe5d6c54" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_630ebb13-7619-48b6-b3f3-db09ecfd1bbd" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ConcentrationRiskByBenchmarkAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DisaggregationOfRevenueTable_6af2b21e-db6b-411c-940c-09b6fe5d6c54" xlink:to="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_630ebb13-7619-48b6-b3f3-db09ecfd1bbd" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskBenchmarkDomain_630ebb13-7619-48b6-b3f3-db09ecfd1bbd_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ConcentrationRiskBenchmarkDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_630ebb13-7619-48b6-b3f3-db09ecfd1bbd" xlink:to="loc_us-gaap_ConcentrationRiskBenchmarkDomain_630ebb13-7619-48b6-b3f3-db09ecfd1bbd_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskBenchmarkDomain_2ec6fa8e-0bf8-4f42-980e-6169e8ad3bd5" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ConcentrationRiskBenchmarkDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_630ebb13-7619-48b6-b3f3-db09ecfd1bbd" xlink:to="loc_us-gaap_ConcentrationRiskBenchmarkDomain_2ec6fa8e-0bf8-4f42-980e-6169e8ad3bd5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueFromContractWithCustomerMember_1a162ebe-85d9-42c8-95dd-0c568efd20c9" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_RevenueFromContractWithCustomerMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConcentrationRiskBenchmarkDomain_2ec6fa8e-0bf8-4f42-980e-6169e8ad3bd5" xlink:to="loc_us-gaap_RevenueFromContractWithCustomerMember_1a162ebe-85d9-42c8-95dd-0c568efd20c9" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskByTypeAxis_aaf72e70-4c71-407e-972c-616f0fbbcbd0" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ConcentrationRiskByTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DisaggregationOfRevenueTable_6af2b21e-db6b-411c-940c-09b6fe5d6c54" xlink:to="loc_us-gaap_ConcentrationRiskByTypeAxis_aaf72e70-4c71-407e-972c-616f0fbbcbd0" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskTypeDomain_aaf72e70-4c71-407e-972c-616f0fbbcbd0_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ConcentrationRiskTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ConcentrationRiskByTypeAxis_aaf72e70-4c71-407e-972c-616f0fbbcbd0" xlink:to="loc_us-gaap_ConcentrationRiskTypeDomain_aaf72e70-4c71-407e-972c-616f0fbbcbd0_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskTypeDomain_93b16383-969b-4142-b816-1a42de22ece4" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ConcentrationRiskTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ConcentrationRiskByTypeAxis_aaf72e70-4c71-407e-972c-616f0fbbcbd0" xlink:to="loc_us-gaap_ConcentrationRiskTypeDomain_93b16383-969b-4142-b816-1a42de22ece4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CustomerConcentrationRiskMember_979b4204-9e59-4858-95c4-da4e2ccbe5e4" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_CustomerConcentrationRiskMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConcentrationRiskTypeDomain_93b16383-969b-4142-b816-1a42de22ece4" xlink:to="loc_us-gaap_CustomerConcentrationRiskMember_979b4204-9e59-4858-95c4-da4e2ccbe5e4" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductOrServiceAxis_6fa0c489-14ab-4431-aafd-8c7b49cde33a" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_ProductOrServiceAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DisaggregationOfRevenueTable_6af2b21e-db6b-411c-940c-09b6fe5d6c54" xlink:to="loc_srt_ProductOrServiceAxis_6fa0c489-14ab-4431-aafd-8c7b49cde33a" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_6fa0c489-14ab-4431-aafd-8c7b49cde33a_default" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_ProductsAndServicesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ProductOrServiceAxis_6fa0c489-14ab-4431-aafd-8c7b49cde33a" xlink:to="loc_srt_ProductsAndServicesDomain_6fa0c489-14ab-4431-aafd-8c7b49cde33a_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_76339af5-1fe7-4496-bd1d-f5dee174eca1" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_ProductsAndServicesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ProductOrServiceAxis_6fa0c489-14ab-4431-aafd-8c7b49cde33a" xlink:to="loc_srt_ProductsAndServicesDomain_76339af5-1fe7-4496-bd1d-f5dee174eca1" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_hnst_TradeAgreementsMember_26b410b9-8e98-4cca-a596-5bc5339085d5" xlink:href="hnst-20240630.xsd#hnst_TradeAgreementsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_76339af5-1fe7-4496-bd1d-f5dee174eca1" xlink:to="loc_hnst_TradeAgreementsMember_26b410b9-8e98-4cca-a596-5bc5339085d5" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ContractWithCustomerSalesChannelAxis_05a0bd0b-add1-4e74-b7e4-01a923947ad3" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ContractWithCustomerSalesChannelAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DisaggregationOfRevenueTable_6af2b21e-db6b-411c-940c-09b6fe5d6c54" xlink:to="loc_us-gaap_ContractWithCustomerSalesChannelAxis_05a0bd0b-add1-4e74-b7e4-01a923947ad3" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ContractWithCustomerSalesChannelDomain_05a0bd0b-add1-4e74-b7e4-01a923947ad3_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ContractWithCustomerSalesChannelDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ContractWithCustomerSalesChannelAxis_05a0bd0b-add1-4e74-b7e4-01a923947ad3" xlink:to="loc_us-gaap_ContractWithCustomerSalesChannelDomain_05a0bd0b-add1-4e74-b7e4-01a923947ad3_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ContractWithCustomerSalesChannelDomain_e492cb9d-e943-48ef-8257-54e5e6c17213" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ContractWithCustomerSalesChannelDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ContractWithCustomerSalesChannelAxis_05a0bd0b-add1-4e74-b7e4-01a923947ad3" xlink:to="loc_us-gaap_ContractWithCustomerSalesChannelDomain_e492cb9d-e943-48ef-8257-54e5e6c17213" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SalesChannelDirectlyToConsumerMember_965c59c5-0727-464c-9621-6b52e207ea53" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_SalesChannelDirectlyToConsumerMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ContractWithCustomerSalesChannelDomain_e492cb9d-e943-48ef-8257-54e5e6c17213" xlink:to="loc_us-gaap_SalesChannelDirectlyToConsumerMember_965c59c5-0727-464c-9621-6b52e207ea53" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskPercentage1_f072d140-1dcb-4b94-9841-4818f28055e8" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ConcentrationRiskPercentage1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisaggregationOfRevenueLineItems_4a008967-853e-4ad3-8b4e-092b8f3c9982" xlink:to="loc_us-gaap_ConcentrationRiskPercentage1_f072d140-1dcb-4b94-9841-4818f28055e8" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_hnst_ContractWithCustomerAssetPeriod_dd08f971-5ce3-4401-a66c-8a38f8598d82" xlink:href="hnst-20240630.xsd#hnst_ContractWithCustomerAssetPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisaggregationOfRevenueLineItems_4a008967-853e-4ad3-8b4e-092b8f3c9982" xlink:to="loc_hnst_ContractWithCustomerAssetPeriod_dd08f971-5ce3-4401-a66c-8a38f8598d82" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_hnst_ContractWithCustomerAssetExtensionPeriod_f7027c10-ed9f-4e4b-8cdc-eb008ff047fe" xlink:href="hnst-20240630.xsd#hnst_ContractWithCustomerAssetExtensionPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisaggregationOfRevenueLineItems_4a008967-853e-4ad3-8b4e-092b8f3c9982" xlink:to="loc_hnst_ContractWithCustomerAssetExtensionPeriod_f7027c10-ed9f-4e4b-8cdc-eb008ff047fe" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_63f91c14-af0b-4fde-9e21-893b081d244e" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisaggregationOfRevenueLineItems_4a008967-853e-4ad3-8b4e-092b8f3c9982" xlink:to="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_63f91c14-af0b-4fde-9e21-893b081d244e" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CostOfRevenue_cd9f0e56-fa42-42cc-81d6-3483de696847" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_CostOfRevenue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisaggregationOfRevenueLineItems_4a008967-853e-4ad3-8b4e-092b8f3c9982" xlink:to="loc_us-gaap_CostOfRevenue_cd9f0e56-fa42-42cc-81d6-3483de696847" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_hnst_ContractWithCustomerAssetImpairment_cae3247e-0163-4ff0-8f39-02efb8d07899" xlink:href="hnst-20240630.xsd#hnst_ContractWithCustomerAssetImpairment"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisaggregationOfRevenueLineItems_4a008967-853e-4ad3-8b4e-092b8f3c9982" xlink:to="loc_hnst_ContractWithCustomerAssetImpairment_cae3247e-0163-4ff0-8f39-02efb8d07899" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_hnst_ContractWithCustomerAssetTransportationCreditUtilization_c7958b1a-e492-4ce7-8f6c-363a1792e6f5" xlink:href="hnst-20240630.xsd#hnst_ContractWithCustomerAssetTransportationCreditUtilization"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisaggregationOfRevenueLineItems_4a008967-853e-4ad3-8b4e-092b8f3c9982" xlink:to="loc_hnst_ContractWithCustomerAssetTransportationCreditUtilization_c7958b1a-e492-4ce7-8f6c-363a1792e6f5" xlink:type="arc" order="6"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://honestco.com/role/FairValueMeasurementsDetails" xlink:type="simple" xlink:href="hnst-20240630.xsd#FairValueMeasurementsDetails"/>
  <link:definitionLink xlink:role="http://honestco.com/role/FairValueMeasurementsDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_a262a1ff-cb30-41bd-bc96-5742fb405103" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_f4a32460-7891-4d39-8ae5-2487cd7e26e5" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_a262a1ff-cb30-41bd-bc96-5742fb405103" xlink:to="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_f4a32460-7891-4d39-8ae5-2487cd7e26e5" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashAndCashEquivalentsAxis_07a0566d-2f9e-4300-a7db-b31204b32669" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_CashAndCashEquivalentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_f4a32460-7891-4d39-8ae5-2487cd7e26e5" xlink:to="loc_us-gaap_CashAndCashEquivalentsAxis_07a0566d-2f9e-4300-a7db-b31204b32669" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsMember_07a0566d-2f9e-4300-a7db-b31204b32669_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_CashAndCashEquivalentsAxis_07a0566d-2f9e-4300-a7db-b31204b32669" xlink:to="loc_us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsMember_07a0566d-2f9e-4300-a7db-b31204b32669_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsMember_b034abac-7c47-44da-969a-fa8b4e719ab5" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_CashAndCashEquivalentsAxis_07a0566d-2f9e-4300-a7db-b31204b32669" xlink:to="loc_us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsMember_b034abac-7c47-44da-969a-fa8b4e719ab5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MoneyMarketFundsMember_0c76ddba-963d-4b06-8188-e038edf8afa3" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_MoneyMarketFundsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsMember_b034abac-7c47-44da-969a-fa8b4e719ab5" xlink:to="loc_us-gaap_MoneyMarketFundsMember_0c76ddba-963d-4b06-8188-e038edf8afa3" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_18d1c64e-8869-4710-8812-4baf6782fc16" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_FairValueByFairValueHierarchyLevelAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_f4a32460-7891-4d39-8ae5-2487cd7e26e5" xlink:to="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_18d1c64e-8869-4710-8812-4baf6782fc16" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_18d1c64e-8869-4710-8812-4baf6782fc16_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_18d1c64e-8869-4710-8812-4baf6782fc16" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_18d1c64e-8869-4710-8812-4baf6782fc16_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_7a7cd996-7bce-44b8-bbd5-77d81ca63c4b" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_18d1c64e-8869-4710-8812-4baf6782fc16" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_7a7cd996-7bce-44b8-bbd5-77d81ca63c4b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel1Member_7302de99-d419-41a4-8af3-f739ded61367" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_FairValueInputsLevel1Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_7a7cd996-7bce-44b8-bbd5-77d81ca63c4b" xlink:to="loc_us-gaap_FairValueInputsLevel1Member_7302de99-d419-41a4-8af3-f739ded61367" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel2Member_30857093-6b89-410b-8a36-c2a295121cf2" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_FairValueInputsLevel2Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_7a7cd996-7bce-44b8-bbd5-77d81ca63c4b" xlink:to="loc_us-gaap_FairValueInputsLevel2Member_30857093-6b89-410b-8a36-c2a295121cf2" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel3Member_4ce96747-4d02-4d79-88e6-8b08dd367097" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_FairValueInputsLevel3Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_7a7cd996-7bce-44b8-bbd5-77d81ca63c4b" xlink:to="loc_us-gaap_FairValueInputsLevel3Member_4ce96747-4d02-4d79-88e6-8b08dd367097" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByMeasurementFrequencyAxis_f4ac8dc1-4ccd-44a8-823d-ac32c190bc63" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_FairValueByMeasurementFrequencyAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_f4a32460-7891-4d39-8ae5-2487cd7e26e5" xlink:to="loc_us-gaap_FairValueByMeasurementFrequencyAxis_f4ac8dc1-4ccd-44a8-823d-ac32c190bc63" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementFrequencyDomain_f4ac8dc1-4ccd-44a8-823d-ac32c190bc63_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_FairValueMeasurementFrequencyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByMeasurementFrequencyAxis_f4ac8dc1-4ccd-44a8-823d-ac32c190bc63" xlink:to="loc_us-gaap_FairValueMeasurementFrequencyDomain_f4ac8dc1-4ccd-44a8-823d-ac32c190bc63_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementFrequencyDomain_08ce1ef4-04ce-4ed2-9165-efd9d1a551df" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_FairValueMeasurementFrequencyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByMeasurementFrequencyAxis_f4ac8dc1-4ccd-44a8-823d-ac32c190bc63" xlink:to="loc_us-gaap_FairValueMeasurementFrequencyDomain_08ce1ef4-04ce-4ed2-9165-efd9d1a551df" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsRecurringMember_dfbe83e9-21f7-403b-a45a-928a6166c36a" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_FairValueMeasurementsRecurringMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementFrequencyDomain_08ce1ef4-04ce-4ed2-9165-efd9d1a551df" xlink:to="loc_us-gaap_FairValueMeasurementsRecurringMember_dfbe83e9-21f7-403b-a45a-928a6166c36a" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashAndCashEquivalentsFairValueDisclosure_aef64e14-6c52-4ad9-8154-a9e6520c6ffa" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_CashAndCashEquivalentsFairValueDisclosure"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_a262a1ff-cb30-41bd-bc96-5742fb405103" xlink:to="loc_us-gaap_CashAndCashEquivalentsFairValueDisclosure_aef64e14-6c52-4ad9-8154-a9e6520c6ffa" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://honestco.com/role/CreditFacilitiesDetails" xlink:type="simple" xlink:href="hnst-20240630.xsd#CreditFacilitiesDetails"/>
  <link:definitionLink xlink:role="http://honestco.com/role/CreditFacilitiesDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditFacilityLineItems_59014f8f-0723-4aca-80a4-5bec86970de5" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_LineOfCreditFacilityLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditFacilityTable_c9d06716-f7ed-432d-97b7-d3153883387e" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_LineOfCreditFacilityTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_59014f8f-0723-4aca-80a4-5bec86970de5" xlink:to="loc_us-gaap_LineOfCreditFacilityTable_c9d06716-f7ed-432d-97b7-d3153883387e" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CreditFacilityAxis_91bf4dc7-23e9-4386-82a2-ac3dd50f9a94" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_CreditFacilityAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LineOfCreditFacilityTable_c9d06716-f7ed-432d-97b7-d3153883387e" xlink:to="loc_us-gaap_CreditFacilityAxis_91bf4dc7-23e9-4386-82a2-ac3dd50f9a94" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CreditFacilityDomain_91bf4dc7-23e9-4386-82a2-ac3dd50f9a94_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_CreditFacilityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_CreditFacilityAxis_91bf4dc7-23e9-4386-82a2-ac3dd50f9a94" xlink:to="loc_us-gaap_CreditFacilityDomain_91bf4dc7-23e9-4386-82a2-ac3dd50f9a94_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CreditFacilityDomain_b2c1c131-6e70-4ab7-bbca-3e6d50e3ac12" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_CreditFacilityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_CreditFacilityAxis_91bf4dc7-23e9-4386-82a2-ac3dd50f9a94" xlink:to="loc_us-gaap_CreditFacilityDomain_b2c1c131-6e70-4ab7-bbca-3e6d50e3ac12" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevolvingCreditFacilityMember_61057a92-86d3-4d2f-b85a-6acf0d156521" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_RevolvingCreditFacilityMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CreditFacilityDomain_b2c1c131-6e70-4ab7-bbca-3e6d50e3ac12" xlink:to="loc_us-gaap_RevolvingCreditFacilityMember_61057a92-86d3-4d2f-b85a-6acf0d156521" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LetterOfCreditMember_1bf7d35b-fd81-46cd-a60d-b6283464ad41" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_LetterOfCreditMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CreditFacilityDomain_b2c1c131-6e70-4ab7-bbca-3e6d50e3ac12" xlink:to="loc_us-gaap_LetterOfCreditMember_1bf7d35b-fd81-46cd-a60d-b6283464ad41" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentAxis_8ee402dd-e20c-40c0-869e-81349cf0ac29" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DebtInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LineOfCreditFacilityTable_c9d06716-f7ed-432d-97b7-d3153883387e" xlink:to="loc_us-gaap_DebtInstrumentAxis_8ee402dd-e20c-40c0-869e-81349cf0ac29" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_8ee402dd-e20c-40c0-869e-81349cf0ac29_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DebtInstrumentAxis_8ee402dd-e20c-40c0-869e-81349cf0ac29" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_8ee402dd-e20c-40c0-869e-81349cf0ac29_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_8fd74f27-c3ea-450d-980a-0be28fccd0fc" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DebtInstrumentAxis_8ee402dd-e20c-40c0-869e-81349cf0ac29" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_8fd74f27-c3ea-450d-980a-0be28fccd0fc" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_hnst_A2023CreditFacilityMember_84788def-4393-4250-a9a3-113ac099437f" xlink:href="hnst-20240630.xsd#hnst_A2023CreditFacilityMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_8fd74f27-c3ea-450d-980a-0be28fccd0fc" xlink:to="loc_hnst_A2023CreditFacilityMember_84788def-4393-4250-a9a3-113ac099437f" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeAxis_f9464f85-be0a-49a1-8295-f909b197d671" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_LongtermDebtTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LineOfCreditFacilityTable_c9d06716-f7ed-432d-97b7-d3153883387e" xlink:to="loc_us-gaap_LongtermDebtTypeAxis_f9464f85-be0a-49a1-8295-f909b197d671" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_f9464f85-be0a-49a1-8295-f909b197d671_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_f9464f85-be0a-49a1-8295-f909b197d671" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_f9464f85-be0a-49a1-8295-f909b197d671_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_2cb9d17f-0d36-492d-8b02-c00d5637a23b" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_f9464f85-be0a-49a1-8295-f909b197d671" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_2cb9d17f-0d36-492d-8b02-c00d5637a23b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditMember_11368abc-cce7-439f-9177-dc8fe9733a08" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_LineOfCreditMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_2cb9d17f-0d36-492d-8b02-c00d5637a23b" xlink:to="loc_us-gaap_LineOfCreditMember_11368abc-cce7-439f-9177-dc8fe9733a08" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeAxis_421d702e-78ad-45c9-ab82-fc9434432d66" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_RangeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LineOfCreditFacilityTable_c9d06716-f7ed-432d-97b7-d3153883387e" xlink:to="loc_srt_RangeAxis_421d702e-78ad-45c9-ab82-fc9434432d66" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_421d702e-78ad-45c9-ab82-fc9434432d66_default" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_421d702e-78ad-45c9-ab82-fc9434432d66" xlink:to="loc_srt_RangeMember_421d702e-78ad-45c9-ab82-fc9434432d66_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_f9ed3907-4fb5-41d7-ab0f-d7630dfbf2cb" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_421d702e-78ad-45c9-ab82-fc9434432d66" xlink:to="loc_srt_RangeMember_f9ed3907-4fb5-41d7-ab0f-d7630dfbf2cb" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MinimumMember_a3f1e703-84b4-4dc0-9a8b-7c4d7a9e2076" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_MinimumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_f9ed3907-4fb5-41d7-ab0f-d7630dfbf2cb" xlink:to="loc_srt_MinimumMember_a3f1e703-84b4-4dc0-9a8b-7c4d7a9e2076" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MaximumMember_a5313d08-9adc-4a27-b744-a86e1e10db22" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_MaximumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_f9ed3907-4fb5-41d7-ab0f-d7630dfbf2cb" xlink:to="loc_srt_MaximumMember_a5313d08-9adc-4a27-b744-a86e1e10db22" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_VariableRateAxis_b37aa8e9-0d54-431f-88e7-bfa01a8dbc24" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_VariableRateAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LineOfCreditFacilityTable_c9d06716-f7ed-432d-97b7-d3153883387e" xlink:to="loc_us-gaap_VariableRateAxis_b37aa8e9-0d54-431f-88e7-bfa01a8dbc24" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_VariableRateDomain_b37aa8e9-0d54-431f-88e7-bfa01a8dbc24_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_VariableRateDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_VariableRateAxis_b37aa8e9-0d54-431f-88e7-bfa01a8dbc24" xlink:to="loc_us-gaap_VariableRateDomain_b37aa8e9-0d54-431f-88e7-bfa01a8dbc24_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_VariableRateDomain_eaef5e26-1f96-4fb7-b8c2-16c628e2dc54" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_VariableRateDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_VariableRateAxis_b37aa8e9-0d54-431f-88e7-bfa01a8dbc24" xlink:to="loc_us-gaap_VariableRateDomain_eaef5e26-1f96-4fb7-b8c2-16c628e2dc54" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SecuredOvernightFinancingRateSofrMember_3b9c2827-abd8-40cc-b9c9-fb2381686541" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_SecuredOvernightFinancingRateSofrMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_VariableRateDomain_eaef5e26-1f96-4fb7-b8c2-16c628e2dc54" xlink:to="loc_us-gaap_SecuredOvernightFinancingRateSofrMember_3b9c2827-abd8-40cc-b9c9-fb2381686541" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PrimeRateMember_780c6daf-c678-4f19-9153-96ba7680f6a0" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_PrimeRateMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_VariableRateDomain_eaef5e26-1f96-4fb7-b8c2-16c628e2dc54" xlink:to="loc_us-gaap_PrimeRateMember_780c6daf-c678-4f19-9153-96ba7680f6a0" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BaseRateMember_d8f66ec6-c3de-4fb9-835c-899ed32a23d2" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_BaseRateMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_VariableRateDomain_eaef5e26-1f96-4fb7-b8c2-16c628e2dc54" xlink:to="loc_us-gaap_BaseRateMember_d8f66ec6-c3de-4fb9-835c-899ed32a23d2" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity_4900b337-8657-400d-923f-47c7f59662a3" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_59014f8f-0723-4aca-80a4-5bec86970de5" xlink:to="loc_us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity_4900b337-8657-400d-923f-47c7f59662a3" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_hnst_LineOfCreditFacilityAccordionFeatureIncreaseLimit_2a1a172e-f462-40e4-ad64-5a0954d48b63" xlink:href="hnst-20240630.xsd#hnst_LineOfCreditFacilityAccordionFeatureIncreaseLimit"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_59014f8f-0723-4aca-80a4-5bec86970de5" xlink:to="loc_hnst_LineOfCreditFacilityAccordionFeatureIncreaseLimit_2a1a172e-f462-40e4-ad64-5a0954d48b63" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_hnst_LineOfCreditFacilityAccordionFeatureHigherBorrowingCapacityOption_2a49c039-368c-4044-8b5c-125cc2478be6" xlink:href="hnst-20240630.xsd#hnst_LineOfCreditFacilityAccordionFeatureHigherBorrowingCapacityOption"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_59014f8f-0723-4aca-80a4-5bec86970de5" xlink:to="loc_hnst_LineOfCreditFacilityAccordionFeatureHigherBorrowingCapacityOption_2a49c039-368c-4044-8b5c-125cc2478be6" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LettersOfCreditOutstandingAmount_04d05c23-d494-47d0-a88b-114b4f19849c" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_LettersOfCreditOutstandingAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_59014f8f-0723-4aca-80a4-5bec86970de5" xlink:to="loc_us-gaap_LettersOfCreditOutstandingAmount_04d05c23-d494-47d0-a88b-114b4f19849c" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditFacilityRemainingBorrowingCapacity_8347369e-7ee6-4ee1-884e-a55bdcb306bf" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_LineOfCreditFacilityRemainingBorrowingCapacity"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_59014f8f-0723-4aca-80a4-5bec86970de5" xlink:to="loc_us-gaap_LineOfCreditFacilityRemainingBorrowingCapacity_8347369e-7ee6-4ee1-884e-a55bdcb306bf" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCredit_791769ab-12b8-4861-85a4-d31b36512866" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_LineOfCredit"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_59014f8f-0723-4aca-80a4-5bec86970de5" xlink:to="loc_us-gaap_LineOfCredit_791769ab-12b8-4861-85a4-d31b36512866" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_hnst_DebtInstrumentSecuredOvernightFinancingRateFloor_823f21d1-e24e-4095-9252-76a13c3bac14" xlink:href="hnst-20240630.xsd#hnst_DebtInstrumentSecuredOvernightFinancingRateFloor"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_59014f8f-0723-4aca-80a4-5bec86970de5" xlink:to="loc_hnst_DebtInstrumentSecuredOvernightFinancingRateFloor_823f21d1-e24e-4095-9252-76a13c3bac14" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentBasisSpreadOnVariableRate1_8dea0d5b-4a1f-4602-8f35-78622a6f05e8" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DebtInstrumentBasisSpreadOnVariableRate1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_59014f8f-0723-4aca-80a4-5bec86970de5" xlink:to="loc_us-gaap_DebtInstrumentBasisSpreadOnVariableRate1_8dea0d5b-4a1f-4602-8f35-78622a6f05e8" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_hnst_DebtInstrumentInterestRateBase_c36e663f-ba80-49a5-aeca-8ab26702e791" xlink:href="hnst-20240630.xsd#hnst_DebtInstrumentInterestRateBase"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_59014f8f-0723-4aca-80a4-5bec86970de5" xlink:to="loc_hnst_DebtInstrumentInterestRateBase_c36e663f-ba80-49a5-aeca-8ab26702e791" xlink:type="arc" order="8"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://honestco.com/role/AccruedExpensesDetails" xlink:type="simple" xlink:href="hnst-20240630.xsd#AccruedExpensesDetails"/>
  <link:definitionLink xlink:role="http://honestco.com/role/AccruedExpensesDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_hnst_ScheduleOfPayablesAndAccrualsLineItems_c9ab6326-469d-4fff-911e-69e53c4decac" xlink:href="hnst-20240630.xsd#hnst_ScheduleOfPayablesAndAccrualsLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_hnst_ScheduleOfPayablesAndAccrualsTable_0a00b2fd-41d1-4042-aa44-f3bb8fe8df83" xlink:href="hnst-20240630.xsd#hnst_ScheduleOfPayablesAndAccrualsTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_hnst_ScheduleOfPayablesAndAccrualsLineItems_c9ab6326-469d-4fff-911e-69e53c4decac" xlink:to="loc_hnst_ScheduleOfPayablesAndAccrualsTable_0a00b2fd-41d1-4042-aa44-f3bb8fe8df83" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_TitleOfIndividualAxis_9ba34994-d746-4c8f-a8f3-ce9eda04389f" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_TitleOfIndividualAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_hnst_ScheduleOfPayablesAndAccrualsTable_0a00b2fd-41d1-4042-aa44-f3bb8fe8df83" xlink:to="loc_srt_TitleOfIndividualAxis_9ba34994-d746-4c8f-a8f3-ce9eda04389f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_TitleOfIndividualWithRelationshipToEntityDomain_9ba34994-d746-4c8f-a8f3-ce9eda04389f_default" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_TitleOfIndividualWithRelationshipToEntityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_TitleOfIndividualAxis_9ba34994-d746-4c8f-a8f3-ce9eda04389f" xlink:to="loc_srt_TitleOfIndividualWithRelationshipToEntityDomain_9ba34994-d746-4c8f-a8f3-ce9eda04389f_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_TitleOfIndividualWithRelationshipToEntityDomain_49932155-d982-4352-b1f2-c9d7626329e8" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_TitleOfIndividualWithRelationshipToEntityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_TitleOfIndividualAxis_9ba34994-d746-4c8f-a8f3-ce9eda04389f" xlink:to="loc_srt_TitleOfIndividualWithRelationshipToEntityDomain_49932155-d982-4352-b1f2-c9d7626329e8" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ExecutiveOfficerMember_23197354-aa3d-4442-aebe-0d4139c85f96" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_ExecutiveOfficerMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_TitleOfIndividualWithRelationshipToEntityDomain_49932155-d982-4352-b1f2-c9d7626329e8" xlink:to="loc_srt_ExecutiveOfficerMember_23197354-aa3d-4442-aebe-0d4139c85f96" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccruedSalariesCurrent_2254d5a8-7fb3-4a72-a03e-d67d30709912" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_AccruedSalariesCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_hnst_ScheduleOfPayablesAndAccrualsLineItems_c9ab6326-469d-4fff-911e-69e53c4decac" xlink:to="loc_us-gaap_AccruedSalariesCurrent_2254d5a8-7fb3-4a72-a03e-d67d30709912" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_hnst_AccruedInventoryPurchases_1717a471-d698-488a-be11-a6de69721032" xlink:href="hnst-20240630.xsd#hnst_AccruedInventoryPurchases"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_hnst_ScheduleOfPayablesAndAccrualsLineItems_c9ab6326-469d-4fff-911e-69e53c4decac" xlink:to="loc_hnst_AccruedInventoryPurchases_1717a471-d698-488a-be11-a6de69721032" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_hnst_AccruedReturnLiabilities_93fd9b3b-2908-4eea-b81f-0300b731e015" xlink:href="hnst-20240630.xsd#hnst_AccruedReturnLiabilities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_hnst_ScheduleOfPayablesAndAccrualsLineItems_c9ab6326-469d-4fff-911e-69e53c4decac" xlink:to="loc_hnst_AccruedReturnLiabilities_93fd9b3b-2908-4eea-b81f-0300b731e015" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLeaseLiabilityCurrent_9ab18474-53ed-4766-adb6-ef3298f28432" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_OperatingLeaseLiabilityCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_hnst_ScheduleOfPayablesAndAccrualsLineItems_c9ab6326-469d-4fff-911e-69e53c4decac" xlink:to="loc_us-gaap_OperatingLeaseLiabilityCurrent_9ab18474-53ed-4766-adb6-ef3298f28432" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestructuringReserveCurrent_a082e101-e865-49af-b3b2-f49adde08935" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_RestructuringReserveCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_hnst_ScheduleOfPayablesAndAccrualsLineItems_c9ab6326-469d-4fff-911e-69e53c4decac" xlink:to="loc_us-gaap_RestructuringReserveCurrent_a082e101-e865-49af-b3b2-f49adde08935" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherAccruedLiabilitiesCurrent_56341fb1-bd6c-434a-8aaf-a3f868a429c6" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_OtherAccruedLiabilitiesCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_hnst_ScheduleOfPayablesAndAccrualsLineItems_c9ab6326-469d-4fff-911e-69e53c4decac" xlink:to="loc_us-gaap_OtherAccruedLiabilitiesCurrent_56341fb1-bd6c-434a-8aaf-a3f868a429c6" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccruedLiabilitiesCurrent_257845ea-319b-4f1a-a8bd-99ca26eb43f5" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_AccruedLiabilitiesCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_hnst_ScheduleOfPayablesAndAccrualsLineItems_c9ab6326-469d-4fff-911e-69e53c4decac" xlink:to="loc_us-gaap_AccruedLiabilitiesCurrent_257845ea-319b-4f1a-a8bd-99ca26eb43f5" xlink:type="arc" order="6"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://honestco.com/role/StockBasedCompensation2021EquityIncentivePlanDetails" xlink:type="simple" xlink:href="hnst-20240630.xsd#StockBasedCompensation2021EquityIncentivePlanDetails"/>
  <link:definitionLink xlink:role="http://honestco.com/role/StockBasedCompensation2021EquityIncentivePlanDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_70ded5d6-5075-4698-9067-08739bcebb28" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_6f220e80-f452-4552-95f7-fe88b5761b8e" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_70ded5d6-5075-4698-9067-08739bcebb28" xlink:to="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_6f220e80-f452-4552-95f7-fe88b5761b8e" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PlanNameAxis_b3edb63d-ba98-4411-99c0-9c4b3260146b" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_PlanNameAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_6f220e80-f452-4552-95f7-fe88b5761b8e" xlink:to="loc_us-gaap_PlanNameAxis_b3edb63d-ba98-4411-99c0-9c4b3260146b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PlanNameDomain_b3edb63d-ba98-4411-99c0-9c4b3260146b_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_PlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_PlanNameAxis_b3edb63d-ba98-4411-99c0-9c4b3260146b" xlink:to="loc_us-gaap_PlanNameDomain_b3edb63d-ba98-4411-99c0-9c4b3260146b_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PlanNameDomain_efa4445f-5f95-455d-b10e-fb0a4a9064d2" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_PlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_PlanNameAxis_b3edb63d-ba98-4411-99c0-9c4b3260146b" xlink:to="loc_us-gaap_PlanNameDomain_efa4445f-5f95-455d-b10e-fb0a4a9064d2" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_hnst_A2021EquityIncentivePlanMember_9ff6c354-38b2-480d-945c-9eb8e0703a4c" xlink:href="hnst-20240630.xsd#hnst_A2021EquityIncentivePlanMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PlanNameDomain_efa4445f-5f95-455d-b10e-fb0a4a9064d2" xlink:to="loc_hnst_A2021EquityIncentivePlanMember_9ff6c354-38b2-480d-945c-9eb8e0703a4c" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AwardTypeAxis_a1a035ef-42a1-453f-b39b-2944989deb20" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_AwardTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_6f220e80-f452-4552-95f7-fe88b5761b8e" xlink:to="loc_us-gaap_AwardTypeAxis_a1a035ef-42a1-453f-b39b-2944989deb20" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_a1a035ef-42a1-453f-b39b-2944989deb20_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AwardTypeAxis_a1a035ef-42a1-453f-b39b-2944989deb20" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_a1a035ef-42a1-453f-b39b-2944989deb20_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_f7c75b75-15dc-47d0-a0b3-bb2fb73b6420" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AwardTypeAxis_a1a035ef-42a1-453f-b39b-2944989deb20" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_f7c75b75-15dc-47d0-a0b3-bb2fb73b6420" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_hnst_IncentiveStockOptionsMember_73a2846e-60c8-4053-9c39-b1ac29f58f7c" xlink:href="hnst-20240630.xsd#hnst_IncentiveStockOptionsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_f7c75b75-15dc-47d0-a0b3-bb2fb73b6420" xlink:to="loc_hnst_IncentiveStockOptionsMember_73a2846e-60c8-4053-9c39-b1ac29f58f7c" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized_420f6085-f037-4b0d-a44d-804c8c01962f" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_70ded5d6-5075-4698-9067-08739bcebb28" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized_420f6085-f037-4b0d-a44d-804c8c01962f" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_hnst_ShareBasedCompensationArrangementByShareBasedPaymentAwardIncreasePeriod_8129d14b-763c-412c-8c25-312ad65b9046" xlink:href="hnst-20240630.xsd#hnst_ShareBasedCompensationArrangementByShareBasedPaymentAwardIncreasePeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_70ded5d6-5075-4698-9067-08739bcebb28" xlink:to="loc_hnst_ShareBasedCompensationArrangementByShareBasedPaymentAwardIncreasePeriod_8129d14b-763c-412c-8c25-312ad65b9046" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardPercentageOfOutstandingStockMaximum_c365927c-4273-472f-a9be-9dbffb865e5c" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardPercentageOfOutstandingStockMaximum"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_70ded5d6-5075-4698-9067-08739bcebb28" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardPercentageOfOutstandingStockMaximum_c365927c-4273-472f-a9be-9dbffb865e5c" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockCapitalSharesReservedForFutureIssuance_63ae1d07-28fe-4e7c-8ee1-f9f330b39943" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_CommonStockCapitalSharesReservedForFutureIssuance"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_70ded5d6-5075-4698-9067-08739bcebb28" xlink:to="loc_us-gaap_CommonStockCapitalSharesReservedForFutureIssuance_63ae1d07-28fe-4e7c-8ee1-f9f330b39943" xlink:type="arc" order="3"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://honestco.com/role/StockBasedCompensationRSUAwardsDetails" xlink:type="simple" xlink:href="hnst-20240630.xsd#StockBasedCompensationRSUAwardsDetails"/>
  <link:definitionLink xlink:role="http://honestco.com/role/StockBasedCompensationRSUAwardsDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_489b4fa6-6a86-418a-a12e-d22563aa844c" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_fd54f726-bc63-45a0-804f-5ce0b624add1" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_489b4fa6-6a86-418a-a12e-d22563aa844c" xlink:to="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_fd54f726-bc63-45a0-804f-5ce0b624add1" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_TitleOfIndividualAxis_822337d6-c069-407e-ba42-fa4dff1f3808" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_TitleOfIndividualAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_fd54f726-bc63-45a0-804f-5ce0b624add1" xlink:to="loc_srt_TitleOfIndividualAxis_822337d6-c069-407e-ba42-fa4dff1f3808" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_TitleOfIndividualWithRelationshipToEntityDomain_822337d6-c069-407e-ba42-fa4dff1f3808_default" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_TitleOfIndividualWithRelationshipToEntityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_TitleOfIndividualAxis_822337d6-c069-407e-ba42-fa4dff1f3808" xlink:to="loc_srt_TitleOfIndividualWithRelationshipToEntityDomain_822337d6-c069-407e-ba42-fa4dff1f3808_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_TitleOfIndividualWithRelationshipToEntityDomain_f7993877-eeb2-47e1-b7e1-1a66afe13ad1" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_TitleOfIndividualWithRelationshipToEntityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_TitleOfIndividualAxis_822337d6-c069-407e-ba42-fa4dff1f3808" xlink:to="loc_srt_TitleOfIndividualWithRelationshipToEntityDomain_f7993877-eeb2-47e1-b7e1-1a66afe13ad1" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_hnst_NonEmployeeDirectorsMember_4efebc16-16eb-4059-abaf-2df1f06cdfd7" xlink:href="hnst-20240630.xsd#hnst_NonEmployeeDirectorsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_TitleOfIndividualWithRelationshipToEntityDomain_f7993877-eeb2-47e1-b7e1-1a66afe13ad1" xlink:to="loc_hnst_NonEmployeeDirectorsMember_4efebc16-16eb-4059-abaf-2df1f06cdfd7" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_hnst_DirectorsOfficersAndEmployeesMember_efce9712-f662-418f-83f1-1558d3125748" xlink:href="hnst-20240630.xsd#hnst_DirectorsOfficersAndEmployeesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_TitleOfIndividualWithRelationshipToEntityDomain_f7993877-eeb2-47e1-b7e1-1a66afe13ad1" xlink:to="loc_hnst_DirectorsOfficersAndEmployeesMember_efce9712-f662-418f-83f1-1558d3125748" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AwardTypeAxis_114b74f5-fe56-46d8-80dc-eaab568dde17" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_AwardTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_fd54f726-bc63-45a0-804f-5ce0b624add1" xlink:to="loc_us-gaap_AwardTypeAxis_114b74f5-fe56-46d8-80dc-eaab568dde17" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_114b74f5-fe56-46d8-80dc-eaab568dde17_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AwardTypeAxis_114b74f5-fe56-46d8-80dc-eaab568dde17" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_114b74f5-fe56-46d8-80dc-eaab568dde17_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_f34a2e4b-9a92-403d-84d8-b54c4757c915" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AwardTypeAxis_114b74f5-fe56-46d8-80dc-eaab568dde17" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_f34a2e4b-9a92-403d-84d8-b54c4757c915" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestrictedStockUnitsRSUMember_797bd364-01de-4753-85ee-9b82ea6de9d0" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_RestrictedStockUnitsRSUMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_f34a2e4b-9a92-403d-84d8-b54c4757c915" xlink:to="loc_us-gaap_RestrictedStockUnitsRSUMember_797bd364-01de-4753-85ee-9b82ea6de9d0" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentsOutstandingRollForward_043a6180-131c-4079-81cf-2009b1c74052" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentsOutstandingRollForward"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_489b4fa6-6a86-418a-a12e-d22563aa844c" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentsOutstandingRollForward_043a6180-131c-4079-81cf-2009b1c74052" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber_d787ce7a-e2b9-4cd3-957e-f32090d99019" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentsOutstandingRollForward_043a6180-131c-4079-81cf-2009b1c74052" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber_d787ce7a-e2b9-4cd3-957e-f32090d99019" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod_b8b282ca-4238-4e3c-8e15-2c0490972188" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentsOutstandingRollForward_043a6180-131c-4079-81cf-2009b1c74052" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod_b8b282ca-4238-4e3c-8e15-2c0490972188" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod_42cd0b65-d503-4772-bcb0-01e13dee3770" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentsOutstandingRollForward_043a6180-131c-4079-81cf-2009b1c74052" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod_42cd0b65-d503-4772-bcb0-01e13dee3770" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod_59e70d5c-0a9b-462d-ab25-4e6ca1ec8039" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentsOutstandingRollForward_043a6180-131c-4079-81cf-2009b1c74052" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod_59e70d5c-0a9b-462d-ab25-4e6ca1ec8039" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber_4c54fe79-62b6-43d0-927b-813602873860" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_6a4a7a39-78f1-4ead-930c-5898c99f67e1" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_489b4fa6-6a86-418a-a12e-d22563aa844c" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_6a4a7a39-78f1-4ead-930c-5898c99f67e1" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue_1c996218-3ddd-41df-b468-7dbc11da6f71" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_6a4a7a39-78f1-4ead-930c-5898c99f67e1" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue_1c996218-3ddd-41df-b468-7dbc11da6f71" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_1381d7e5-f010-4d9d-956c-5feadb3c658a" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_6a4a7a39-78f1-4ead-930c-5898c99f67e1" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_1381d7e5-f010-4d9d-956c-5feadb3c658a" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue_d93b4bd9-35d5-4875-bc94-d014b2f736b2" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_6a4a7a39-78f1-4ead-930c-5898c99f67e1" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue_d93b4bd9-35d5-4875-bc94-d014b2f736b2" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue_8db0a61d-359f-4c73-bf0d-6610c00abe1e" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_6a4a7a39-78f1-4ead-930c-5898c99f67e1" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue_8db0a61d-359f-4c73-bf0d-6610c00abe1e" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue_ed29ca35-2734-46e1-a86e-8f0ca053c737" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://honestco.com/role/StockBasedCompensationRSUAwardsNarrativeDetails" xlink:type="simple" xlink:href="hnst-20240630.xsd#StockBasedCompensationRSUAwardsNarrativeDetails"/>
  <link:definitionLink xlink:role="http://honestco.com/role/StockBasedCompensationRSUAwardsNarrativeDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_2c2a836f-f0c1-4957-aac0-02cb4277d6e8" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_bd234f3e-84da-4668-a319-0f93357d08ca" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_2c2a836f-f0c1-4957-aac0-02cb4277d6e8" xlink:to="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_bd234f3e-84da-4668-a319-0f93357d08ca" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AwardTypeAxis_392c9d2d-db20-4422-807f-b9f3ece7fa96" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_AwardTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_bd234f3e-84da-4668-a319-0f93357d08ca" xlink:to="loc_us-gaap_AwardTypeAxis_392c9d2d-db20-4422-807f-b9f3ece7fa96" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_392c9d2d-db20-4422-807f-b9f3ece7fa96_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AwardTypeAxis_392c9d2d-db20-4422-807f-b9f3ece7fa96" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_392c9d2d-db20-4422-807f-b9f3ece7fa96_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_0e3a474d-a40c-4b86-b9b6-3ef8e0e2751f" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AwardTypeAxis_392c9d2d-db20-4422-807f-b9f3ece7fa96" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_0e3a474d-a40c-4b86-b9b6-3ef8e0e2751f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestrictedStockUnitsRSUMember_4a37a99a-03b3-4aad-a96d-64a6bca31d9c" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_RestrictedStockUnitsRSUMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_0e3a474d-a40c-4b86-b9b6-3ef8e0e2751f" xlink:to="loc_us-gaap_RestrictedStockUnitsRSUMember_4a37a99a-03b3-4aad-a96d-64a6bca31d9c" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized_15503646-7821-47ae-9396-f71af6a23555" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_2c2a836f-f0c1-4957-aac0-02cb4277d6e8" xlink:to="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized_15503646-7821-47ae-9396-f71af6a23555" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1_b24c95b7-55aa-41ce-beb2-8dfb9e594ea1" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_2c2a836f-f0c1-4957-aac0-02cb4277d6e8" xlink:to="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1_b24c95b7-55aa-41ce-beb2-8dfb9e594ea1" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://honestco.com/role/StockBasedCompensation2021EmployeeStockPurchasePlanDetails" xlink:type="simple" xlink:href="hnst-20240630.xsd#StockBasedCompensation2021EmployeeStockPurchasePlanDetails"/>
  <link:definitionLink xlink:role="http://honestco.com/role/StockBasedCompensation2021EmployeeStockPurchasePlanDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_5d8ab5de-0244-456f-a8c1-e64e1cd8007c" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_35ae7d6a-1252-4cb4-b900-37d1954be600" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_5d8ab5de-0244-456f-a8c1-e64e1cd8007c" xlink:to="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_35ae7d6a-1252-4cb4-b900-37d1954be600" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AwardTypeAxis_238020d6-419b-4bef-a191-304bfdca9e23" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_AwardTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_35ae7d6a-1252-4cb4-b900-37d1954be600" xlink:to="loc_us-gaap_AwardTypeAxis_238020d6-419b-4bef-a191-304bfdca9e23" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_238020d6-419b-4bef-a191-304bfdca9e23_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AwardTypeAxis_238020d6-419b-4bef-a191-304bfdca9e23" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_238020d6-419b-4bef-a191-304bfdca9e23_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_0b8bbbc5-7953-46b4-bbdf-832aedf29578" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AwardTypeAxis_238020d6-419b-4bef-a191-304bfdca9e23" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_0b8bbbc5-7953-46b4-bbdf-832aedf29578" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeStockMember_2f63f4cf-e59b-40d0-8b88-34ba92bfc019" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_EmployeeStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_0b8bbbc5-7953-46b4-bbdf-832aedf29578" xlink:to="loc_us-gaap_EmployeeStockMember_2f63f4cf-e59b-40d0-8b88-34ba92bfc019" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PlanNameAxis_38a2e1a3-04d1-44ab-806d-4e9a40a30754" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_PlanNameAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_35ae7d6a-1252-4cb4-b900-37d1954be600" xlink:to="loc_us-gaap_PlanNameAxis_38a2e1a3-04d1-44ab-806d-4e9a40a30754" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PlanNameDomain_38a2e1a3-04d1-44ab-806d-4e9a40a30754_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_PlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_PlanNameAxis_38a2e1a3-04d1-44ab-806d-4e9a40a30754" xlink:to="loc_us-gaap_PlanNameDomain_38a2e1a3-04d1-44ab-806d-4e9a40a30754_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PlanNameDomain_b2ca9bc9-7929-4068-947b-1bd8064dec9e" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_PlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_PlanNameAxis_38a2e1a3-04d1-44ab-806d-4e9a40a30754" xlink:to="loc_us-gaap_PlanNameDomain_b2ca9bc9-7929-4068-947b-1bd8064dec9e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_hnst_A2021EmployeeStockPurchasePlanMember_9fded366-a59d-468f-acd9-db6d6b5be73a" xlink:href="hnst-20240630.xsd#hnst_A2021EmployeeStockPurchasePlanMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PlanNameDomain_b2ca9bc9-7929-4068-947b-1bd8064dec9e" xlink:to="loc_hnst_A2021EmployeeStockPurchasePlanMember_9fded366-a59d-468f-acd9-db6d6b5be73a" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockCapitalSharesReservedForFutureIssuance_d8dfabcc-dfc5-434c-a687-3da7268dfe6e" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_CommonStockCapitalSharesReservedForFutureIssuance"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_5d8ab5de-0244-456f-a8c1-e64e1cd8007c" xlink:to="loc_us-gaap_CommonStockCapitalSharesReservedForFutureIssuance_d8dfabcc-dfc5-434c-a687-3da7268dfe6e" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_hnst_ShareBasedCompensationArrangementByShareBasedPaymentAwardIncreasePeriod_be34bcc6-e0d7-44e8-a157-6b99e83cf5f5" xlink:href="hnst-20240630.xsd#hnst_ShareBasedCompensationArrangementByShareBasedPaymentAwardIncreasePeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_5d8ab5de-0244-456f-a8c1-e64e1cd8007c" xlink:to="loc_hnst_ShareBasedCompensationArrangementByShareBasedPaymentAwardIncreasePeriod_be34bcc6-e0d7-44e8-a157-6b99e83cf5f5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardPercentageOfOutstandingStockMaximum_5ee613ba-4688-41b8-b3ca-cc817b67b93f" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardPercentageOfOutstandingStockMaximum"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_5d8ab5de-0244-456f-a8c1-e64e1cd8007c" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardPercentageOfOutstandingStockMaximum_5ee613ba-4688-41b8-b3ca-cc817b67b93f" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfAdditionalSharesAuthorized_da30c897-f371-4165-99d8-aad36dfeb295" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfAdditionalSharesAuthorized"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_5d8ab5de-0244-456f-a8c1-e64e1cd8007c" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfAdditionalSharesAuthorized_da30c897-f371-4165-99d8-aad36dfeb295" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardPurchasePriceOfCommonStockPercent_d0c1094f-ff10-451a-b9cf-65a10ea0499a" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardPurchasePriceOfCommonStockPercent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_5d8ab5de-0244-456f-a8c1-e64e1cd8007c" xlink:to="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardPurchasePriceOfCommonStockPercent_d0c1094f-ff10-451a-b9cf-65a10ea0499a" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_hnst_ShareBasedCompensationArrangementByShareBasedPaymentAwardPurchasePeriod_a523c30e-caa9-4687-881f-d10a8b3f7e93" xlink:href="hnst-20240630.xsd#hnst_ShareBasedCompensationArrangementByShareBasedPaymentAwardPurchasePeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_5d8ab5de-0244-456f-a8c1-e64e1cd8007c" xlink:to="loc_hnst_ShareBasedCompensationArrangementByShareBasedPaymentAwardPurchasePeriod_a523c30e-caa9-4687-881f-d10a8b3f7e93" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardSharesIssuedInPeriod_dca590df-9db7-4925-bcc5-bb76d216fcd0" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardSharesIssuedInPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_5d8ab5de-0244-456f-a8c1-e64e1cd8007c" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardSharesIssuedInPeriod_dca590df-9db7-4925-bcc5-bb76d216fcd0" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant_a412a468-46f6-48ad-83af-6d47a7130a9d" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_5d8ab5de-0244-456f-a8c1-e64e1cd8007c" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant_a412a468-46f6-48ad-83af-6d47a7130a9d" xlink:type="arc" order="7"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://honestco.com/role/StockBasedCompensationScheduleofSharebasedPaymentAwardStockOptionsValuationAssumptionsDetails" xlink:type="simple" xlink:href="hnst-20240630.xsd#StockBasedCompensationScheduleofSharebasedPaymentAwardStockOptionsValuationAssumptionsDetails"/>
  <link:definitionLink xlink:role="http://honestco.com/role/StockBasedCompensationScheduleofSharebasedPaymentAwardStockOptionsValuationAssumptionsDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_433550ed-ab88-4d9d-a111-8abcfb984581" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_01db7f29-4fa9-4727-b06a-a033d12c401e" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_433550ed-ab88-4d9d-a111-8abcfb984581" xlink:to="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_01db7f29-4fa9-4727-b06a-a033d12c401e" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AwardTypeAxis_0721b690-f1af-4b85-8a1d-1f1a78024969" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_AwardTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_01db7f29-4fa9-4727-b06a-a033d12c401e" xlink:to="loc_us-gaap_AwardTypeAxis_0721b690-f1af-4b85-8a1d-1f1a78024969" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_0721b690-f1af-4b85-8a1d-1f1a78024969_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AwardTypeAxis_0721b690-f1af-4b85-8a1d-1f1a78024969" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_0721b690-f1af-4b85-8a1d-1f1a78024969_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_8524c621-f3f1-49af-813f-09e313fcbd0e" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AwardTypeAxis_0721b690-f1af-4b85-8a1d-1f1a78024969" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_8524c621-f3f1-49af-813f-09e313fcbd0e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeStockOptionMember_e0712d94-77c3-41c8-9f43-e1f9e89e2e39" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_EmployeeStockOptionMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_8524c621-f3f1-49af-813f-09e313fcbd0e" xlink:to="loc_us-gaap_EmployeeStockOptionMember_e0712d94-77c3-41c8-9f43-e1f9e89e2e39" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeAxis_4fd4c272-2ce3-4200-a4a9-1df175efd2f1" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_RangeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_01db7f29-4fa9-4727-b06a-a033d12c401e" xlink:to="loc_srt_RangeAxis_4fd4c272-2ce3-4200-a4a9-1df175efd2f1" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_4fd4c272-2ce3-4200-a4a9-1df175efd2f1_default" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_4fd4c272-2ce3-4200-a4a9-1df175efd2f1" xlink:to="loc_srt_RangeMember_4fd4c272-2ce3-4200-a4a9-1df175efd2f1_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_a39e5841-d09b-4664-ae96-f11edd23466e" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_4fd4c272-2ce3-4200-a4a9-1df175efd2f1" xlink:to="loc_srt_RangeMember_a39e5841-d09b-4664-ae96-f11edd23466e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MinimumMember_f551c0ce-b7ee-4572-8116-4d007eeeaaa0" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_MinimumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_a39e5841-d09b-4664-ae96-f11edd23466e" xlink:to="loc_srt_MinimumMember_f551c0ce-b7ee-4572-8116-4d007eeeaaa0" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MaximumMember_08d26a6e-75e8-440b-b11c-5cc32494bd65" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_MaximumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_a39e5841-d09b-4664-ae96-f11edd23466e" xlink:to="loc_srt_MaximumMember_08d26a6e-75e8-440b-b11c-5cc32494bd65" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardFairValueAssumptionsExpectedTerm1_6a9a4042-a738-4ff2-8556-912b8918de49" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardFairValueAssumptionsExpectedTerm1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_433550ed-ab88-4d9d-a111-8abcfb984581" xlink:to="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardFairValueAssumptionsExpectedTerm1_6a9a4042-a738-4ff2-8556-912b8918de49" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRateMinimum_689edaf2-f3c2-4eb0-9c1c-d7a89efe2529" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRateMinimum"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_433550ed-ab88-4d9d-a111-8abcfb984581" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRateMinimum_689edaf2-f3c2-4eb0-9c1c-d7a89efe2529" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRateMaximum_5b0a051c-4743-43d8-bc14-da425270e1eb" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRateMaximum"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_433550ed-ab88-4d9d-a111-8abcfb984581" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRateMaximum_5b0a051c-4743-43d8-bc14-da425270e1eb" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate_ee9fb27d-0e91-4cd7-8081-ca753de90cd0" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_433550ed-ab88-4d9d-a111-8abcfb984581" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate_ee9fb27d-0e91-4cd7-8081-ca753de90cd0" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate_d487f2f6-7264-47bc-92c1-4a52774a0476" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_433550ed-ab88-4d9d-a111-8abcfb984581" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate_d487f2f6-7264-47bc-92c1-4a52774a0476" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_847b78a7-d1a6-49da-84cd-a99febff9a8e" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_433550ed-ab88-4d9d-a111-8abcfb984581" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_847b78a7-d1a6-49da-84cd-a99febff9a8e" xlink:type="arc" order="5"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://honestco.com/role/StockBasedCompensation2023InducementPlanDetails" xlink:type="simple" xlink:href="hnst-20240630.xsd#StockBasedCompensation2023InducementPlanDetails"/>
  <link:definitionLink xlink:role="http://honestco.com/role/StockBasedCompensation2023InducementPlanDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_b366aa23-c4ac-4d7c-99f6-3c14116d09fe" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_03a00ed0-94bd-4e9a-9c31-82cf400f23c9" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_b366aa23-c4ac-4d7c-99f6-3c14116d09fe" xlink:to="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_03a00ed0-94bd-4e9a-9c31-82cf400f23c9" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PlanNameAxis_672b40ee-5eaf-4be5-8129-109a7c358ea4" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_PlanNameAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_03a00ed0-94bd-4e9a-9c31-82cf400f23c9" xlink:to="loc_us-gaap_PlanNameAxis_672b40ee-5eaf-4be5-8129-109a7c358ea4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PlanNameDomain_672b40ee-5eaf-4be5-8129-109a7c358ea4_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_PlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_PlanNameAxis_672b40ee-5eaf-4be5-8129-109a7c358ea4" xlink:to="loc_us-gaap_PlanNameDomain_672b40ee-5eaf-4be5-8129-109a7c358ea4_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PlanNameDomain_fd58285d-aa04-4d44-9d1f-732fa8c59ec6" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_PlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_PlanNameAxis_672b40ee-5eaf-4be5-8129-109a7c358ea4" xlink:to="loc_us-gaap_PlanNameDomain_fd58285d-aa04-4d44-9d1f-732fa8c59ec6" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_hnst_A2023InducementPlanMember_340e6c35-dd63-4214-941e-768a5d973eee" xlink:href="hnst-20240630.xsd#hnst_A2023InducementPlanMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PlanNameDomain_fd58285d-aa04-4d44-9d1f-732fa8c59ec6" xlink:to="loc_hnst_A2023InducementPlanMember_340e6c35-dd63-4214-941e-768a5d973eee" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockCapitalSharesReservedForFutureIssuance_ec0166c9-f1da-4812-a55b-2448ac321786" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_CommonStockCapitalSharesReservedForFutureIssuance"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_b366aa23-c4ac-4d7c-99f6-3c14116d09fe" xlink:to="loc_us-gaap_CommonStockCapitalSharesReservedForFutureIssuance_ec0166c9-f1da-4812-a55b-2448ac321786" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant_04e0cc54-c402-42fe-a818-b0f4410687ad" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_b366aa23-c4ac-4d7c-99f6-3c14116d09fe" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant_04e0cc54-c402-42fe-a818-b0f4410687ad" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://honestco.com/role/StockBasedCompensationStockbasedCompensationExpenseDetails" xlink:type="simple" xlink:href="hnst-20240630.xsd#StockBasedCompensationStockbasedCompensationExpenseDetails"/>
  <link:definitionLink xlink:role="http://honestco.com/role/StockBasedCompensationStockbasedCompensationExpenseDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsLineItems_1515db3b-b407-4e0e-8230-5fced9706d5e" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfEmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsTable_02f315c3-54ab-4959-bc60-b93d4a385a3b" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ScheduleOfEmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsLineItems_1515db3b-b407-4e0e-8230-5fced9706d5e" xlink:to="loc_us-gaap_ScheduleOfEmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsTable_02f315c3-54ab-4959-bc60-b93d4a385a3b" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementLocationAxis_af2c0ace-bad6-48f1-a1e9-9d3da545cfda" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_IncomeStatementLocationAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfEmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsTable_02f315c3-54ab-4959-bc60-b93d4a385a3b" xlink:to="loc_us-gaap_IncomeStatementLocationAxis_af2c0ace-bad6-48f1-a1e9-9d3da545cfda" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementLocationDomain_af2c0ace-bad6-48f1-a1e9-9d3da545cfda_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_IncomeStatementLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_IncomeStatementLocationAxis_af2c0ace-bad6-48f1-a1e9-9d3da545cfda" xlink:to="loc_us-gaap_IncomeStatementLocationDomain_af2c0ace-bad6-48f1-a1e9-9d3da545cfda_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementLocationDomain_9a4ff22e-7425-4063-83e7-fadfa2264f94" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_IncomeStatementLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_IncomeStatementLocationAxis_af2c0ace-bad6-48f1-a1e9-9d3da545cfda" xlink:to="loc_us-gaap_IncomeStatementLocationDomain_9a4ff22e-7425-4063-83e7-fadfa2264f94" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SellingGeneralAndAdministrativeExpensesMember_f193185f-713f-4df7-9e9b-689655649f8f" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_SellingGeneralAndAdministrativeExpensesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementLocationDomain_9a4ff22e-7425-4063-83e7-fadfa2264f94" xlink:to="loc_us-gaap_SellingGeneralAndAdministrativeExpensesMember_f193185f-713f-4df7-9e9b-689655649f8f" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ResearchAndDevelopmentExpenseMember_49583b91-7ade-40f7-9ac3-7debd1f3334d" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ResearchAndDevelopmentExpenseMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementLocationDomain_9a4ff22e-7425-4063-83e7-fadfa2264f94" xlink:to="loc_us-gaap_ResearchAndDevelopmentExpenseMember_49583b91-7ade-40f7-9ac3-7debd1f3334d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_TitleOfIndividualAxis_34181ec2-270c-47f4-8989-f8c0b65e04f0" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_TitleOfIndividualAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfEmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsTable_02f315c3-54ab-4959-bc60-b93d4a385a3b" xlink:to="loc_srt_TitleOfIndividualAxis_34181ec2-270c-47f4-8989-f8c0b65e04f0" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_TitleOfIndividualWithRelationshipToEntityDomain_34181ec2-270c-47f4-8989-f8c0b65e04f0_default" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_TitleOfIndividualWithRelationshipToEntityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_TitleOfIndividualAxis_34181ec2-270c-47f4-8989-f8c0b65e04f0" xlink:to="loc_srt_TitleOfIndividualWithRelationshipToEntityDomain_34181ec2-270c-47f4-8989-f8c0b65e04f0_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_TitleOfIndividualWithRelationshipToEntityDomain_2f917251-1bde-4b92-bd57-e921ad5def77" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_TitleOfIndividualWithRelationshipToEntityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_TitleOfIndividualAxis_34181ec2-270c-47f4-8989-f8c0b65e04f0" xlink:to="loc_srt_TitleOfIndividualWithRelationshipToEntityDomain_2f917251-1bde-4b92-bd57-e921ad5def77" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_hnst_CompanysFounderMember_9a3d7758-1327-4f4f-9090-576617416cc2" xlink:href="hnst-20240630.xsd#hnst_CompanysFounderMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_TitleOfIndividualWithRelationshipToEntityDomain_2f917251-1bde-4b92-bd57-e921ad5def77" xlink:to="loc_hnst_CompanysFounderMember_9a3d7758-1327-4f4f-9090-576617416cc2" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_hnst_FormerChiefExecutiveOfficerMember_66ad8b9e-cbef-477a-84ea-778a0ad1f14f" xlink:href="hnst-20240630.xsd#hnst_FormerChiefExecutiveOfficerMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_TitleOfIndividualWithRelationshipToEntityDomain_2f917251-1bde-4b92-bd57-e921ad5def77" xlink:to="loc_hnst_FormerChiefExecutiveOfficerMember_66ad8b9e-cbef-477a-84ea-778a0ad1f14f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AllocatedShareBasedCompensationExpense_56858b0a-4ee5-4757-8a06-9921c08f54de" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_AllocatedShareBasedCompensationExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsLineItems_1515db3b-b407-4e0e-8230-5fced9706d5e" xlink:to="loc_us-gaap_AllocatedShareBasedCompensationExpense_56858b0a-4ee5-4757-8a06-9921c08f54de" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://honestco.com/role/NetIncomeLossperShareAttributabletoCommonStockholdersPotentiallyDilutiveSharesExcludedFromComputationofDilutedNetIncomeLossPerShareDetails" xlink:type="simple" xlink:href="hnst-20240630.xsd#NetIncomeLossperShareAttributabletoCommonStockholdersPotentiallyDilutiveSharesExcludedFromComputationofDilutedNetIncomeLossPerShareDetails"/>
  <link:definitionLink xlink:role="http://honestco.com/role/NetIncomeLossperShareAttributabletoCommonStockholdersPotentiallyDilutiveSharesExcludedFromComputationofDilutedNetIncomeLossPerShareDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems_16027f7c-6c94-4da8-bd14-f079826fef1e" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTable_4a1691d7-9206-4827-8834-ce309a0fc430" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems_16027f7c-6c94-4da8-bd14-f079826fef1e" xlink:to="loc_us-gaap_ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTable_4a1691d7-9206-4827-8834-ce309a0fc430" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis_33066c30-da27-4591-8028-24f674eda23a" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTable_4a1691d7-9206-4827-8834-ce309a0fc430" xlink:to="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis_33066c30-da27-4591-8028-24f674eda23a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AntidilutiveSecuritiesNameDomain_33066c30-da27-4591-8028-24f674eda23a_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_AntidilutiveSecuritiesNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis_33066c30-da27-4591-8028-24f674eda23a" xlink:to="loc_us-gaap_AntidilutiveSecuritiesNameDomain_33066c30-da27-4591-8028-24f674eda23a_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AntidilutiveSecuritiesNameDomain_d2a7dced-15dc-4c7f-9c81-8272f6dea378" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_AntidilutiveSecuritiesNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis_33066c30-da27-4591-8028-24f674eda23a" xlink:to="loc_us-gaap_AntidilutiveSecuritiesNameDomain_d2a7dced-15dc-4c7f-9c81-8272f6dea378" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeStockOptionMember_19348959-82c7-4502-a662-5658dc9a3a01" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_EmployeeStockOptionMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AntidilutiveSecuritiesNameDomain_d2a7dced-15dc-4c7f-9c81-8272f6dea378" xlink:to="loc_us-gaap_EmployeeStockOptionMember_19348959-82c7-4502-a662-5658dc9a3a01" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestrictedStockUnitsRSUMember_8b0b7baf-8e86-4fca-bd6d-39c8bd64deed" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_RestrictedStockUnitsRSUMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AntidilutiveSecuritiesNameDomain_d2a7dced-15dc-4c7f-9c81-8272f6dea378" xlink:to="loc_us-gaap_RestrictedStockUnitsRSUMember_8b0b7baf-8e86-4fca-bd6d-39c8bd64deed" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeStockMember_6cb8d54e-7df3-4b9e-8f88-a38455c07adf" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_EmployeeStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AntidilutiveSecuritiesNameDomain_d2a7dced-15dc-4c7f-9c81-8272f6dea378" xlink:to="loc_us-gaap_EmployeeStockMember_6cb8d54e-7df3-4b9e-8f88-a38455c07adf" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount_dcb635a1-d9af-4cb3-9a4f-baa7fb025f52" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems_16027f7c-6c94-4da8-bd14-f079826fef1e" xlink:to="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount_dcb635a1-d9af-4cb3-9a4f-baa7fb025f52" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://honestco.com/role/LeasesAdditionalInformationDetails" xlink:type="simple" xlink:href="hnst-20240630.xsd#LeasesAdditionalInformationDetails"/>
  <link:definitionLink xlink:role="http://honestco.com/role/LeasesAdditionalInformationDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeLeaseDescriptionLineItems_726051ba-778d-47c7-bde8-7f52c2e00f96" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_LesseeLeaseDescriptionLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeLeaseDescriptionTable_882610d8-2204-492e-85b3-32e3c0b624a8" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_LesseeLeaseDescriptionTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_726051ba-778d-47c7-bde8-7f52c2e00f96" xlink:to="loc_us-gaap_LesseeLeaseDescriptionTable_882610d8-2204-492e-85b3-32e3c0b624a8" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeAxis_53e99915-00f0-4ead-9d52-9892989d4bbf" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_RangeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LesseeLeaseDescriptionTable_882610d8-2204-492e-85b3-32e3c0b624a8" xlink:to="loc_srt_RangeAxis_53e99915-00f0-4ead-9d52-9892989d4bbf" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_53e99915-00f0-4ead-9d52-9892989d4bbf_default" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_53e99915-00f0-4ead-9d52-9892989d4bbf" xlink:to="loc_srt_RangeMember_53e99915-00f0-4ead-9d52-9892989d4bbf_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_c8b7ef21-bb1b-466b-8775-f6f4e2dd77a1" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_53e99915-00f0-4ead-9d52-9892989d4bbf" xlink:to="loc_srt_RangeMember_c8b7ef21-bb1b-466b-8775-f6f4e2dd77a1" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MinimumMember_755467e7-60df-4880-bbc5-0dd089d314f4" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_MinimumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_c8b7ef21-bb1b-466b-8775-f6f4e2dd77a1" xlink:to="loc_srt_MinimumMember_755467e7-60df-4880-bbc5-0dd089d314f4" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MaximumMember_cae396a8-f9fd-4778-ae3a-998e1279012f" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_MaximumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_c8b7ef21-bb1b-466b-8775-f6f4e2dd77a1" xlink:to="loc_srt_MaximumMember_cae396a8-f9fd-4778-ae3a-998e1279012f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeOperatingLeaseRemainingLeaseTerm_56affef8-ac2b-4286-8dc6-c13989d00204" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_LesseeOperatingLeaseRemainingLeaseTerm"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_726051ba-778d-47c7-bde8-7f52c2e00f96" xlink:to="loc_us-gaap_LesseeOperatingLeaseRemainingLeaseTerm_56affef8-ac2b-4286-8dc6-c13989d00204" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeFinanceLeaseRemainingLeaseTerm_2d50cd53-996a-4cc7-9849-def3ca877ec3" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_LesseeFinanceLeaseRemainingLeaseTerm"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_726051ba-778d-47c7-bde8-7f52c2e00f96" xlink:to="loc_us-gaap_LesseeFinanceLeaseRemainingLeaseTerm_2d50cd53-996a-4cc7-9849-def3ca877ec3" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RightOfUseAssetObtainedInExchangeForFinanceLeaseLiability_a765ca29-4807-4a62-8b0c-0a4ee9db18ee" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_RightOfUseAssetObtainedInExchangeForFinanceLeaseLiability"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_726051ba-778d-47c7-bde8-7f52c2e00f96" xlink:to="loc_us-gaap_RightOfUseAssetObtainedInExchangeForFinanceLeaseLiability_a765ca29-4807-4a62-8b0c-0a4ee9db18ee" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RightOfUseAssetObtainedInExchangeForOperatingLeaseLiability_64e1f8d0-6ab0-4b7b-9520-c5de8829bd77" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_RightOfUseAssetObtainedInExchangeForOperatingLeaseLiability"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_726051ba-778d-47c7-bde8-7f52c2e00f96" xlink:to="loc_us-gaap_RightOfUseAssetObtainedInExchangeForOperatingLeaseLiability_64e1f8d0-6ab0-4b7b-9520-c5de8829bd77" xlink:type="arc" order="3"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://honestco.com/role/RestructuringScheduleofRestructuringReservebyTypeofCostDetails" xlink:type="simple" xlink:href="hnst-20240630.xsd#RestructuringScheduleofRestructuringReservebyTypeofCostDetails"/>
  <link:definitionLink xlink:role="http://honestco.com/role/RestructuringScheduleofRestructuringReservebyTypeofCostDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestructuringCostAndReserveLineItems_f25932e3-60eb-4b97-910e-e36445addf0c" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_RestructuringCostAndReserveLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfRestructuringAndRelatedCostsTable_b034942c-b5c1-4142-843c-c0a0af0437ee" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ScheduleOfRestructuringAndRelatedCostsTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_RestructuringCostAndReserveLineItems_f25932e3-60eb-4b97-910e-e36445addf0c" xlink:to="loc_us-gaap_ScheduleOfRestructuringAndRelatedCostsTable_b034942c-b5c1-4142-843c-c0a0af0437ee" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestructuringCostAndReserveAxis_4aaeab52-291d-4586-9ff0-48006ffe5cf3" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_RestructuringCostAndReserveAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRestructuringAndRelatedCostsTable_b034942c-b5c1-4142-843c-c0a0af0437ee" xlink:to="loc_us-gaap_RestructuringCostAndReserveAxis_4aaeab52-291d-4586-9ff0-48006ffe5cf3" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TypeOfRestructuringDomain_4aaeab52-291d-4586-9ff0-48006ffe5cf3_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_TypeOfRestructuringDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RestructuringCostAndReserveAxis_4aaeab52-291d-4586-9ff0-48006ffe5cf3" xlink:to="loc_us-gaap_TypeOfRestructuringDomain_4aaeab52-291d-4586-9ff0-48006ffe5cf3_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TypeOfRestructuringDomain_0881850f-bfbb-4414-80cb-07233b6e0003" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_TypeOfRestructuringDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RestructuringCostAndReserveAxis_4aaeab52-291d-4586-9ff0-48006ffe5cf3" xlink:to="loc_us-gaap_TypeOfRestructuringDomain_0881850f-bfbb-4414-80cb-07233b6e0003" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeSeveranceMember_bb2de28a-3f32-4a64-89bf-f32aea10da7c" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_EmployeeSeveranceMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TypeOfRestructuringDomain_0881850f-bfbb-4414-80cb-07233b6e0003" xlink:to="loc_us-gaap_EmployeeSeveranceMember_bb2de28a-3f32-4a64-89bf-f32aea10da7c" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_hnst_ImpairmentInValueOfAssetsMember_302dbd57-ec1e-48cd-b794-e5aa00093e84" xlink:href="hnst-20240630.xsd#hnst_ImpairmentInValueOfAssetsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TypeOfRestructuringDomain_0881850f-bfbb-4414-80cb-07233b6e0003" xlink:to="loc_hnst_ImpairmentInValueOfAssetsMember_302dbd57-ec1e-48cd-b794-e5aa00093e84" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ContractTerminationMember_f5af9133-56d1-4f05-9ab4-eb16f285a103" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ContractTerminationMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TypeOfRestructuringDomain_0881850f-bfbb-4414-80cb-07233b6e0003" xlink:to="loc_us-gaap_ContractTerminationMember_f5af9133-56d1-4f05-9ab4-eb16f285a103" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_hnst_InventoryReservesMember_2cb73e56-4265-44c3-a5d1-6288794bd4df" xlink:href="hnst-20240630.xsd#hnst_InventoryReservesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TypeOfRestructuringDomain_0881850f-bfbb-4414-80cb-07233b6e0003" xlink:to="loc_hnst_InventoryReservesMember_2cb73e56-4265-44c3-a5d1-6288794bd4df" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestructuringPlanAxis_a35ae863-517f-4c2d-9b64-3c7ec8816178" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_RestructuringPlanAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRestructuringAndRelatedCostsTable_b034942c-b5c1-4142-843c-c0a0af0437ee" xlink:to="loc_us-gaap_RestructuringPlanAxis_a35ae863-517f-4c2d-9b64-3c7ec8816178" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestructuringPlanDomain_a35ae863-517f-4c2d-9b64-3c7ec8816178_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_RestructuringPlanDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RestructuringPlanAxis_a35ae863-517f-4c2d-9b64-3c7ec8816178" xlink:to="loc_us-gaap_RestructuringPlanDomain_a35ae863-517f-4c2d-9b64-3c7ec8816178_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestructuringPlanDomain_f627e92e-0364-46fb-835d-3cad68ab505b" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_RestructuringPlanDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RestructuringPlanAxis_a35ae863-517f-4c2d-9b64-3c7ec8816178" xlink:to="loc_us-gaap_RestructuringPlanDomain_f627e92e-0364-46fb-835d-3cad68ab505b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_hnst_TransformationInitiativeMember_ccb04013-d0ee-4cc2-8c36-b12551b432e7" xlink:href="hnst-20240630.xsd#hnst_TransformationInitiativeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RestructuringPlanDomain_f627e92e-0364-46fb-835d-3cad68ab505b" xlink:to="loc_hnst_TransformationInitiativeMember_ccb04013-d0ee-4cc2-8c36-b12551b432e7" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestructuringReserveRollForward_c8d69c62-2f72-4877-9479-fc7834196c79" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_RestructuringReserveRollForward"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RestructuringCostAndReserveLineItems_f25932e3-60eb-4b97-910e-e36445addf0c" xlink:to="loc_us-gaap_RestructuringReserveRollForward_c8d69c62-2f72-4877-9479-fc7834196c79" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestructuringReserve_0e079988-0595-4068-9e3f-f410622d7b2f" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_RestructuringReserve"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RestructuringReserveRollForward_c8d69c62-2f72-4877-9479-fc7834196c79" xlink:to="loc_us-gaap_RestructuringReserve_0e079988-0595-4068-9e3f-f410622d7b2f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_hnst_RestructuringChargesAdjustments_b640e9f4-cb78-48c5-b1c5-dcbfc83e6439" xlink:href="hnst-20240630.xsd#hnst_RestructuringChargesAdjustments"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RestructuringReserveRollForward_c8d69c62-2f72-4877-9479-fc7834196c79" xlink:to="loc_hnst_RestructuringChargesAdjustments_b640e9f4-cb78-48c5-b1c5-dcbfc83e6439" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PaymentsForRestructuring_9fc75bef-ee33-4224-9ff5-5db33f3c7fba" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_PaymentsForRestructuring"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RestructuringReserveRollForward_c8d69c62-2f72-4877-9479-fc7834196c79" xlink:to="loc_us-gaap_PaymentsForRestructuring_9fc75bef-ee33-4224-9ff5-5db33f3c7fba" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestructuringReserveSettledWithoutCash2_9acceff0-d026-4cd2-a5d6-15831f4d389d" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_RestructuringReserveSettledWithoutCash2"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RestructuringReserveRollForward_c8d69c62-2f72-4877-9479-fc7834196c79" xlink:to="loc_us-gaap_RestructuringReserveSettledWithoutCash2_9acceff0-d026-4cd2-a5d6-15831f4d389d" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestructuringReserve_6a1f003e-b034-49df-b6af-5c72ee8633a8" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_RestructuringReserve"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://honestco.com/role/RestructuringNarrativeDetails" xlink:type="simple" xlink:href="hnst-20240630.xsd#RestructuringNarrativeDetails"/>
  <link:definitionLink xlink:role="http://honestco.com/role/RestructuringNarrativeDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestructuringCostAndReserveLineItems_e1f5e25e-0ef8-41e0-8579-8eac01155175" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_RestructuringCostAndReserveLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfRestructuringAndRelatedCostsTable_7ebfb26d-c3c1-4c36-99f2-6dcc22646786" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ScheduleOfRestructuringAndRelatedCostsTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_RestructuringCostAndReserveLineItems_e1f5e25e-0ef8-41e0-8579-8eac01155175" xlink:to="loc_us-gaap_ScheduleOfRestructuringAndRelatedCostsTable_7ebfb26d-c3c1-4c36-99f2-6dcc22646786" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestructuringCostAndReserveAxis_90435e05-9884-4987-9a26-5d5f3b3a8432" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_RestructuringCostAndReserveAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRestructuringAndRelatedCostsTable_7ebfb26d-c3c1-4c36-99f2-6dcc22646786" xlink:to="loc_us-gaap_RestructuringCostAndReserveAxis_90435e05-9884-4987-9a26-5d5f3b3a8432" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TypeOfRestructuringDomain_90435e05-9884-4987-9a26-5d5f3b3a8432_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_TypeOfRestructuringDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RestructuringCostAndReserveAxis_90435e05-9884-4987-9a26-5d5f3b3a8432" xlink:to="loc_us-gaap_TypeOfRestructuringDomain_90435e05-9884-4987-9a26-5d5f3b3a8432_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TypeOfRestructuringDomain_ab060c16-e30f-41cd-920e-851e8d543079" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_TypeOfRestructuringDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RestructuringCostAndReserveAxis_90435e05-9884-4987-9a26-5d5f3b3a8432" xlink:to="loc_us-gaap_TypeOfRestructuringDomain_ab060c16-e30f-41cd-920e-851e8d543079" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeSeveranceMember_15316cfb-d85d-40c1-83d4-7799382bc1ba" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_EmployeeSeveranceMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TypeOfRestructuringDomain_ab060c16-e30f-41cd-920e-851e8d543079" xlink:to="loc_us-gaap_EmployeeSeveranceMember_15316cfb-d85d-40c1-83d4-7799382bc1ba" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestructuringReserve_876cae4f-ab49-461c-9b5e-bf1818d2db51" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_RestructuringReserve"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RestructuringCostAndReserveLineItems_e1f5e25e-0ef8-41e0-8579-8eac01155175" xlink:to="loc_us-gaap_RestructuringReserve_876cae4f-ab49-461c-9b5e-bf1818d2db51" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://fasb.org/us-gaap/role/eedm/ExtensibleEnumerationLists" xlink:type="simple" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-roles-2024.xsd#eedm"/>
  <link:definitionLink xlink:role="http://fasb.org/us-gaap/role/eedm/ExtensibleEnumerationLists" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilitiesCurrentAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_LiabilitiesCurrentAbstract"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccruedLiabilitiesCurrent" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_AccruedLiabilitiesCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesCurrentAbstract" xlink:to="loc_us-gaap_AccruedLiabilitiesCurrent" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetsAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_AssetsAbstract"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentAndFinanceLeaseRightOfUseAssetAfterAccumulatedDepreciationAndAmortization" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_PropertyPlantAndEquipmentAndFinanceLeaseRightOfUseAssetAfterAccumulatedDepreciationAndAmortization"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentAndFinanceLeaseRightOfUseAssetAfterAccumulatedDepreciationAndAmortization" xlink:type="arc" order="1"/>
  </link:definitionLink>
</link:linkbase>
