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

    <schemaVersion>X0306</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2013-04-25</periodOfReport>

    <notSubjectToSection16>1</notSubjectToSection16>

    <issuer>
        <issuerCik>0001375247</issuerCik>
        <issuerName>Obagi Medical Products, Inc.</issuerName>
        <issuerTradingSymbol>OMPI</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001307207</rptOwnerCik>
            <rptOwnerName>Leslie Kristina M</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O OBAGI MEDICAL PRODUCTS, INC.</rptOwnerStreet1>
            <rptOwnerStreet2>3760 KILROY AIRPORT WAY, SUITE 500</rptOwnerStreet2>
            <rptOwnerCity>LONG BEACH</rptOwnerCity>
            <rptOwnerState>CA</rptOwnerState>
            <rptOwnerZipCode>90806</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>
                <footnoteId id="F1"/>
            </securityTitle>
            <transactionDate>
                <value>2013-04-25</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>D</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>4890</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>24.00</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>0</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <derivativeTable></derivativeTable>

    <footnotes>
        <footnote id="F1">At the effective time of the merger, these shares of restricted stock immediately vested in full and were converted into the right to receive $24.00 per share in cash, without interest (less any applicable withholding tax), under the terms of the Agreement and Plan of Merger, dated March 19, 2013, among the issuer, Odysseus Acquisition Corp., Valeant Pharmaceuticals International, and Valeant Pharmaceuticals International, Inc., as amended, and the issuer's 2005 Stock Incentive Plan, as amended, and as approved by the issuer's Board of Directors.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>Kristina M. Leslie</signatureName>
        <signatureDate>2013-04-29</signatureDate>
    </ownerSignature>
</ownershipDocument>
