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

    <schemaVersion>X0303</schemaVersion>

    <documentType>4/A</documentType>

    <periodOfReport>2009-12-03</periodOfReport>

    <dateOfOriginalSubmission>2009-12-07</dateOfOriginalSubmission>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001113809</issuerCik>
        <issuerName>BUILD A BEAR WORKSHOP INC</issuerName>
        <issuerTradingSymbol>BBW</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001373604</rptOwnerCik>
            <rptOwnerName>BML Investment Partners, L.P.</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>65 E CEDAR - SUITE 2</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>ZIONSVILLE</rptOwnerCity>
            <rptOwnerState>IN</rptOwnerState>
            <rptOwnerZipCode>46077</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle></officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001373603</rptOwnerCik>
            <rptOwnerName>Leonard Braden Michael</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>65 E CEDAR - SUITE 2</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>ZIONSVILLE</rptOwnerCity>
            <rptOwnerState>IN</rptOwnerState>
            <rptOwnerZipCode>46077</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>1</isOther>
            <officerTitle></officerTitle>
            <otherText>Managing Member</otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2009-12-03</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>P</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>14300</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>4.58</value>
                    <footnoteId id="F1"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>2125500</value>
                    <footnoteId id="F2"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>100000</value>
                    <footnoteId id="F3"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
    </nonDerivativeTable>

    <derivativeTable></derivativeTable>

    <footnotes>
        <footnote id="F1">Represents the purchase of 14,300 shares in [ 42  ] separate transactions, ranging in price from $4.55 to $4.59, resulting in a weighted average purchase price per share of $4.58.  The reporting person will provide, upon request by the SEC staff, the Issuer or a security holder of the Issuer, full information regarding the number of shares purchased at each separate price within the range.</footnote>
        <footnote id="F2">These shares are owned directly by BML Investment Partners, L.P., a ten percent owner of the Issuer.  BML Capital Management, LLC is the sole general partner of BML Investment Partners, L.P. and Braden M. Leonard is the managing member of BML Capital Management, LLC.  Mr. Leonard disclaims indirect beneficial ownership of these shares of common stock except to the extent of his pecuniary interest therein, and the inclusion of these shares in this Form 4 shall not be deemed an admission of his indirect beneficial ownership of all of the reported shares for purposes of Section 16 or for any other purpose.</footnote>
        <footnote id="F3">These shares are directly owned by Braden M. Leonard.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>BML Investment Partners, L.P. by Braden M Leonard</signatureName>
        <signatureDate>2009-12-07</signatureDate>
    </ownerSignature>
</ownershipDocument>
