<SEC-DOCUMENT>0000920371-15-000128.txt : 20150820
<SEC-HEADER>0000920371-15-000128.hdr.sgml : 20150820
<ACCEPTANCE-DATETIME>20150820115409
ACCESSION NUMBER:		0000920371-15-000128
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20150818
FILED AS OF DATE:		20150820
DATE AS OF CHANGE:		20150820

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			SIMPSON MANUFACTURING CO INC /CA/
		CENTRAL INDEX KEY:			0000920371
		STANDARD INDUSTRIAL CLASSIFICATION:	CUTLERY, HANDTOOLS & GENERAL HARDWARE [3420]
		IRS NUMBER:				943196943
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		5956 W LAS POSITAS BLVD
		CITY:			PLEASANTON
		STATE:			CA
		ZIP:			94588
		BUSINESS PHONE:		9255609000

	MAIL ADDRESS:	
		STREET 1:		5956 W LAS POSITAS BLVD
		CITY:			PLEASANTON
		STATE:			CA
		ZIP:			94588

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Mackenzie Jeffrey Eric
		CENTRAL INDEX KEY:			0001452573

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-13429
		FILM NUMBER:		151065761

	MAIL ADDRESS:	
		STREET 1:		5956 W. LAS POSITAS BLVD.
		CITY:			PLEASANTON
		STATE:			CA
		ZIP:			94566
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>wf-form4_144008603930904.xml
<DESCRIPTION>FORM 4
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0306</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2015-08-18</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000920371</issuerCik>
        <issuerName>SIMPSON MANUFACTURING CO INC /CA/</issuerName>
        <issuerTradingSymbol>SSD</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001452573</rptOwnerCik>
            <rptOwnerName>Mackenzie Jeffrey Eric</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>5956 W. LAS POSITAS BLVD.</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>PLEASANTON</rptOwnerCity>
            <rptOwnerState>CA</rptOwnerState>
            <rptOwnerZipCode>94588</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>Vice President</officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock (RSUs awarded Febuary 3, 2014)</value>
            </securityTitle>
            <transactionDate>
                <value>2015-08-18</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>121</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>36.8348</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>969</value>
                    <footnoteId id="F1"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock (RSUs awarded February 6, 2013)</value>
            </securityTitle>
            <transactionDate>
                <value>2015-08-18</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>3607</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>36.8348</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>3625</value>
                    <footnoteId id="F2"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock (RSUs awarded January 30, 2012)</value>
            </securityTitle>
            <transactionDate>
                <value>2015-08-18</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>3272</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>36.8348</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>1669</value>
                    <footnoteId id="F3"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock (RSUs awarded February 2, 2015)</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>1090</value>
                    <footnoteId id="F4"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>4</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
    </nonDerivativeTable>

    <derivativeTable></derivativeTable>

    <footnotes>
        <footnote id="F1">Amount includes 969 shares of restricted stock units (RSUs) awarded on February 3, 2014. RSUs vest one fourth on each of the award date and the first, second and third anniversaries of the award date. The 969 shares are net of the number of shares expected to be withheld to cover the estimated income taxes due on vesting.</footnote>
        <footnote id="F2">Amount includes 3,625 shares of restricted stock units (RSUs) awarded on February 6, 2013. RSUs vest one fourth on each of the award date and the first, second and third anniversaries of the award date. The 3,625 shares are net of the number of shares expected to be withheld to cover the estimated income taxes due on vesting.</footnote>
        <footnote id="F3">Amount includes 1,669 shares of restricted stock units (RSUs) awarded on January 30, 2012. RSUs vested one fourth on each of the award date and the first, second and third anniversaries of the award date. Amount was increased by 111 shares to reflect the difference between the number of shares that was expected to be withheld to cover the estimated income taxes due on vesting (estimated on January 30, 2012, the date of the award) and the actual number of shares that was withheld on vesting of the RSUs.</footnote>
        <footnote id="F4">Amount includes 1,090 shares of restricted stock units (RSUs) awarded on February 2, 2015. RSUs vest one fourth on each of the award date and the first, second and third anniversaries of the award date. The 1,090 shares are net of the number of shares expected to be withheld to cover the estimated income taxes due on vesting.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>/s/JEFFREY E. MACKENZIE</signatureName>
        <signatureDate>2015-08-20</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
