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

    <schemaVersion>X0508</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2025-05-14</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>

    <aff10b5One>0</aff10b5One>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2025-05-14</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>46400</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>65.25</value>
                    <footnoteId id="F2"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                    <footnoteId id="F1"/>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>743207</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2025-05-14</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>19400</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>66.18</value>
                    <footnoteId id="F3"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                    <footnoteId id="F1"/>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>723807</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2025-05-14</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>200</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>66.92</value>
                    <footnoteId id="F4"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                    <footnoteId id="F1"/>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>723607</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2025-05-15</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>5180</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>63.77</value>
                    <footnoteId id="F5"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                    <footnoteId id="F1"/>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>718427</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <derivativeTable></derivativeTable>

    <footnotes>
        <footnote id="F1">All shares reported sold herein were sold for personal tax and estate planning purposes.</footnote>
        <footnote id="F2">The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $64.88 to $65.87, inclusive. The reporting person undertakes to provide to Spectrum Brands Holdings, Inc. (the &quot;Company&quot;), any security holder of the Company or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the ranges set forth in footnotes (2) to (5) to this Form 4.</footnote>
        <footnote id="F3">The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $65.89 to $66.50, inclusive.</footnote>
        <footnote id="F4">The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $66.90 to $66.95, inclusive.</footnote>
        <footnote id="F5">The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $63.10 to $64.01, inclusive.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>/s/ Laurel McKellips, Attorney-in-fact for David M. Maura</signatureName>
        <signatureDate>2025-05-16</signatureDate>
    </ownerSignature>
</ownershipDocument>
[{"type": "4", "sequence": "1", "filename": "wk-form4_1747429407.xml", "description": "FORM 4", "secsgml_size_bytes": 8838}]
X0508
4
2025-05-14
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
0
Common Stock
2025-05-14
4
S
0
46400
65.25
D
743207
D
Common Stock
2025-05-14
4
S
0
19400
66.18
D
723807
D
Common Stock
2025-05-14
4
S
0
200
66.92
D
723607
D
Common Stock
2025-05-15
4
S
0
5180
63.77
D
718427
D
All shares reported sold herein were sold for personal tax and estate planning purposes.
The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $64.88 to $65.87, inclusive. The reporting person undertakes to provide to Spectrum Brands Holdings, Inc. (the "Company"), any security holder of the Company or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the ranges set forth in footnotes (2) to (5) to this Form 4.
The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $65.89 to $66.50, inclusive.
The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $66.90 to $66.95, inclusive.
The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $63.10 to $64.01, inclusive.
/s/ Laurel McKellips, Attorney-in-fact for David M. Maura
2025-05-16