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

    <schemaVersion>X0306</schemaVersion>

    <documentType>4/A</documentType>

    <periodOfReport>2016-02-22</periodOfReport>

    <dateOfOriginalSubmission>2016-03-11</dateOfOriginalSubmission>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001552800</issuerCik>
        <issuerName>TILE SHOP HOLDINGS, INC.</issuerName>
        <issuerTradingSymbol>TTS</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001555414</rptOwnerCik>
            <rptOwnerName>NABRON INTERNATIONAL INC.</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>2ND FLOOR, LE PRINCE DE GALLES</rptOwnerStreet1>
            <rptOwnerStreet2>3-5 AVENUE DES CITRONNIERS</rptOwnerStreet2>
            <rptOwnerCity>MONACO</rptOwnerCity>
            <rptOwnerState>O9</rptOwnerState>
            <rptOwnerZipCode>MC98000</rptOwnerZipCode>
            <rptOwnerStateDescription>MONACO</rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle></officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2016-03-08</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>21217</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>12.896</value>
                    <footnoteId id="F4"/>
                    <footnoteId id="F1"/>
                    <footnoteId id="F5"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>6261320</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                    <footnoteId id="F2"/>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2016-03-10</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>33255</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>14.0594</value>
                    <footnoteId id="F4"/>
                    <footnoteId id="F3"/>
                    <footnoteId id="F5"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>6078065</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                    <footnoteId id="F2"/>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <derivativeTable></derivativeTable>

    <footnotes>
        <footnote id="F1">The price in Column 4 is a weighted average price. The prices actually received ranged from $12.80 to $13.11.</footnote>
        <footnote id="F2">Raymond Long Sing Tang, Jill Marie Franklin, and Louise Mary Garbarino are the directors of the reporting person and exercise voting and investment power over these securities. The reporting person and each of its directors disclaim beneficial ownership of these securities except to the extent of their respective pecuniary interests therein, and this report shall not be deemed an admission that the reporting person or any of its directors is the beneficial owner of such securities for Section 16 or any other purpose.</footnote>
        <footnote id="F3">The price in Column 4 is a weighted average price. The prices actually received ranged from $14.00 to $14.64.</footnote>
        <footnote id="F4">The reporting person has provided to the issuer, and will provide to any security holder of the issuer, or the SEC staff, upon request, information regarding the number of shares sold at each price within the range for all transactions reported in this Form 4 utilizing an average weighted price.</footnote>
        <footnote id="F5">The Form 4 filed on March 11, 2016 reported that 21,217 shares were sold on March 8, 2016 at a price of $12.796 and that 33,255 shares were sold on March 10, 2016 at a price of $14.0094.  The reporting person actually sold 21,217 shares on March 8, 2016 at a price of $12.896 and 33,255 shares on March 10, 2016 at a price of $14.0594. This Form 4 is being filed to correct the transaction prices on these two dates.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>/s/ Paul D. Broude by Power of Attorney</signatureName>
        <signatureDate>2015-03-15</signatureDate>
    </ownerSignature>
</ownershipDocument>
