<?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>0001365833</rptOwnerCik>
            <rptOwnerName>Maura David M</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>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>Executive Chairman and CEO</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>15817</value>
                    <footnoteId id="F1"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>589398</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 December 6, 2024 if Reporting Person is an employee of the Issuer on such date.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>/s/ Rich Bretwisch, Attorney-in-fact for David M. Maura</signatureName>
        <signatureDate>2021-12-17</signatureDate>
    </ownerSignature>
</ownershipDocument>
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X0306
4
2021-12-15
0
0000109177
Spectrum Brands Holdings, Inc.
SPB
0001365833
Maura David M
C/O SPECTRUM BRANDS HOLDINGS, INC.
3001 DEMING WAY
MIDDLETON
WI
53562
1
1
0
0
Executive Chairman and CEO
Common Stock
2021-12-15
4
A
0
15817
0
A
589398
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 December 6, 2024 if Reporting Person is an employee of the Issuer on such date.
/s/ Rich Bretwisch, Attorney-in-fact for David M. Maura
2021-12-17