<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0306</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2021-12-15</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000109177</issuerCik>
        <issuerName>Spectrum Brands Holdings, Inc.</issuerName>
        <issuerTradingSymbol>SPB</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001857303</rptOwnerCik>
            <rptOwnerName>Campbell Leslie Lloyd</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O SPECTRUM BRANDS HOLDINGS, INC</rptOwnerStreet1>
            <rptOwnerStreet2>3001 DEMING WAY</rptOwnerStreet2>
            <rptOwnerCity>MIDDLETON</rptOwnerCity>
            <rptOwnerState>WI</rptOwnerState>
            <rptOwnerZipCode>53562</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle></officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2021-12-15</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>1528</value>
                    <footnoteId id="F1"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>2295</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <derivativeTable></derivativeTable>

    <footnotes>
        <footnote id="F1">Reporting Person was awarded restricted stock units which are settled in shares of common stock of the Issuer and which are scheduled to vest on October 1, 2022 if the Reporting Person is a director of the Issuer on such date.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>/s/ Rich Bretwisch, Attorney-in-fact for Leslie L. Campbell</signatureName>
        <signatureDate>2021-12-17</signatureDate>
    </ownerSignature>
</ownershipDocument>
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X0306
4
2021-12-15
0
0000109177
Spectrum Brands Holdings, Inc.
SPB
0001857303
Campbell Leslie Lloyd
C/O SPECTRUM BRANDS HOLDINGS, INC
3001 DEMING WAY
MIDDLETON
WI
53562
1
0
0
0
Common Stock
2021-12-15
4
A
0
1528
0
A
2295
D
Reporting Person was awarded restricted stock units which are settled in shares of common stock of the Issuer and which are scheduled to vest on October 1, 2022 if the Reporting Person is a director of the Issuer on such date.
/s/ Rich Bretwisch, Attorney-in-fact for Leslie L. Campbell
2021-12-17