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

    <schemaVersion>X0609</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2026-05-15</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001397911</issuerCik>
        <issuerName>LPL Financial Holdings Inc.</issuerName>
        <issuerTradingSymbol>LPLA</issuerTradingSymbol>
        <issuerForeignTradingSymbol></issuerForeignTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001179702</rptOwnerCik>
            <rptOwnerName>EBERHART PAULETT</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerNonUSAddressFlag>false</rptOwnerNonUSAddressFlag>
            <rptOwnerStreet1>C/O LPL FINANCIAL HOLDINGS INC.</rptOwnerStreet1>
            <rptOwnerStreet2>4707 EXECUTIVE DRIVE</rptOwnerStreet2>
            <rptOwnerCity>SAN DIEGO</rptOwnerCity>
            <rptOwnerState>CA</rptOwnerState>
            <rptOwnerZipCode>92121</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <aff10b5One>0</aff10b5One>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2026-05-15</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>712</value>
                    <footnoteId id="F1"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>17755</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <derivativeTable></derivativeTable>

    <footnotes>
        <footnote id="F1">Represents stock units granted under the Issuer's 2021 Omnibus Equity Incentive Plan. Each stock unit represents the right to receive one share of common stock and is scheduled to vest in full on May 20, 2027. These stock units are subject to a written deferral election under the Issuer's Non-Employee Director Deferred Compensation Plan pursuant to which the reporting person elected to defer receipt of the equity portion of the annual retainer under the Issuer's Non-Employee Director Compensation Policy.</footnote>
    </footnotes>

    <remarks>The signatory is signing on behalf of Paulett Eberhart pursuant to a Power of Attorney dated November 25, 2024.</remarks>

    <ownerSignature>
        <signatureName>/s/ Robert S. Hatfield III, attorney-in-fact</signatureName>
        <signatureDate>2026-05-19</signatureDate>
    </ownerSignature>
</ownershipDocument>
