<SUBMISSION>
<ACCESSION-NUMBER>0000920371-03-000032
<TYPE>4
<PUBLIC-DOCUMENT-COUNT>1
<PERIOD>20030606
<FILING-DATE>20030609
<REPORTING-OWNER>
<OWNER-DATA>
<CONFORMED-NAME>CHEIT EARL F
<CIK>0001035244
</OWNER-DATA>
<FILING-VALUES>
<FORM-TYPE>4
<ACT>34
<FILE-NUMBER>001-13429
<FILM-NUMBER>03737709
</FILING-VALUES>
<BUSINESS-ADDRESS>
<STREET1>4637 CHABOT DRIVE
<STREET2>SUITE 200
<CITY>PLESANTON
<STATE>CA
<ZIP>94588
</BUSINESS-ADDRESS>
<MAIL-ADDRESS>
<STREET2>4637 CHABOT DRIVE SUITE 200
<CITY>PLEASENTON
<STATE>CA
<ZIP>94588
</MAIL-ADDRESS>
</REPORTING-OWNER>
<ISSUER>
<COMPANY-DATA>
<CONFORMED-NAME>SIMPSON MANUFACTURING CO INC /CA/
<CIK>0000920371
<ASSIGNED-SIC>3420
<IRS-NUMBER>943196943
<STATE-OF-INCORPORATION>DE
<FISCAL-YEAR-END>1231
</COMPANY-DATA>
<BUSINESS-ADDRESS>
<STREET1>4120 DUBLILN BLVD STE 400
<CITY>DUBLIN
<STATE>CA
<ZIP>94568
<PHONE>9255609000
</BUSINESS-ADDRESS>
<MAIL-ADDRESS>
<STREET1>4120 DUBLIN BLVD STE 400
<CITY>DUBLIN
<STATE>CA
<ZIP>94568
</MAIL-ADDRESS>
</ISSUER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>edgar.xml
<DESCRIPTION>PRIMARY DOCUMENT
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>
    <schemaVersion>X0101</schemaVersion>

    <documentType>4</documentType><periodOfReport>2003-06-06</periodOfReport>
    <issuer>
        <issuerCik>0000920371</issuerCik>
        <issuerName>SIMPSON MANUFACTURING CO INC /CA/</issuerName>
        <issuerTradingSymbol>NYSE:SSD</issuerTradingSymbol></issuer><reportingOwner><reportingOwnerId>
            <rptOwnerCik>0001035244</rptOwnerCik>
            <rptOwnerName>CHEIT EARL F</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>  </rptOwnerStreet1>
            <rptOwnerStreet2>  </rptOwnerStreet2>
            <rptOwnerCity>  </rptOwnerCity>
            <rptOwnerState>  </rptOwnerState>
            <rptOwnerZipCode>  </rptOwnerZipCode>
        </reportingOwnerAddress>
            <reportingOwnerRelationship>
<isDirector>1</isDirector><isOfficer>0</isOfficer><isTenPercentOwner>0</isTenPercentOwner><isOther>0</isOther></reportingOwnerRelationship></reportingOwner><derivativeSecurity><securityTitle><value>Options on Common Stock</value></securityTitle><conversionOrExercisePrice><value>33.95</value></conversionOrExercisePrice><transactionDate><value>2003-06-06</value></transactionDate><transactionCoding><transactionFormType>4</transactionFormType><transactionCode>A</transactionCode><equitySwapInvolved>0</equitySwapInvolved></transactionCoding><transactionAmounts><transactionShares><value>1000</value></transactionShares><transactionValue><value>33.95</value></transactionValue><transactionAcquiredDisposedCode><value>A</value></transactionAcquiredDisposedCode></transactionAmounts><exerciseDate><value>2003-02-14</value></exerciseDate><expirationDate><value>2010-02-13</value></expirationDate><underlyingSecurity><underlyingSecurityTitle><value>Common Stock</value></underlyingSecurityTitle><underlyingSecurityShares><value>1000</value></underlyingSecurityShares></underlyingSecurity><postTransactionAmounts><sharesOwnedFollowingTransaction><value>1000</value></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>D</value></directOrIndirectOwnership><natureOfOwnership><value></value></natureOfOwnership></ownershipNature></derivativeSecurity><derivativeSecurity><securityTitle><value>Options on Common Stock</value></securityTitle><conversionOrExercisePrice><value>14.625</value></conversionOrExercisePrice><transactionDate><value>1988-08-08</value></transactionDate><transactionCoding><transactionFormType>4</transactionFormType><transactionCode>J</transactionCode><equitySwapInvolved>0</equitySwapInvolved><footnoteId id="F1"/></transactionCoding><transactionAmounts><transactionShares><value>0</value></transactionShares><transactionValue><value>14.625</value></transactionValue><transactionAcquiredDisposedCode><value>A</value></transactionAcquiredDisposedCode></transactionAmounts><exerciseDate><value>1997-02-15</value></exerciseDate><expirationDate><value>2004-02-14</value></expirationDate><underlyingSecurity><underlyingSecurityTitle><value>Common Stock</value></underlyingSecurityTitle><underlyingSecurityShares><value>1000</value></underlyingSecurityShares></underlyingSecurity><postTransactionAmounts><sharesOwnedFollowingTransaction><value>1000</value></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>D</value></directOrIndirectOwnership><natureOfOwnership><value></value></natureOfOwnership></ownershipNature></derivativeSecurity><derivativeSecurity><securityTitle><value>Options on Common Stock</value></securityTitle><conversionOrExercisePrice><value>18.6563</value></conversionOrExercisePrice><transactionDate><value>1988-08-08</value></transactionDate><transactionCoding><transactionFormType>4</transactionFormType><transactionCode>J</transactionCode><equitySwapInvolved>0</equitySwapInvolved><footnoteId id="F1"/></transactionCoding><transactionAmounts><transactionShares><value>0</value></transactionShares><transactionValue><value>18.6563</value></transactionValue><transactionAcquiredDisposedCode><value>A</value></transactionAcquiredDisposedCode></transactionAmounts><exerciseDate><value>1998-02-13</value></exerciseDate><expirationDate><value>2005-02-12</value></expirationDate><underlyingSecurity><underlyingSecurityTitle><value>Common Stock</value></underlyingSecurityTitle><underlyingSecurityShares><value>1000</value></underlyingSecurityShares></underlyingSecurity><postTransactionAmounts><sharesOwnedFollowingTransaction><value>1000</value></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>D</value></directOrIndirectOwnership><natureOfOwnership><value></value></natureOfOwnership></ownershipNature></derivativeSecurity><derivativeSecurity><securityTitle><value>Options on Common Stock</value></securityTitle><conversionOrExercisePrice><value>18.3125</value></conversionOrExercisePrice><transactionDate><value>1988-08-08</value></transactionDate><transactionCoding><transactionFormType>4</transactionFormType><transactionCode>J</transactionCode><equitySwapInvolved>0</equitySwapInvolved><footnoteId id="F1"/></transactionCoding><transactionAmounts><transactionShares><value>0</value></transactionShares><transactionValue><value>18.3125</value></transactionValue><transactionAcquiredDisposedCode><value>A</value></transactionAcquiredDisposedCode></transactionAmounts><exerciseDate><value>1999-02-12</value></exerciseDate><expirationDate><value>2006-02-11</value></expirationDate><underlyingSecurity><underlyingSecurityTitle><value>Common Stock</value></underlyingSecurityTitle><underlyingSecurityShares><value>1000</value></underlyingSecurityShares></underlyingSecurity><postTransactionAmounts><sharesOwnedFollowingTransaction><value>1000</value></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>D</value></directOrIndirectOwnership><natureOfOwnership><value></value></natureOfOwnership></ownershipNature></derivativeSecurity><derivativeSecurity><securityTitle><value>Options on Common Stock</value></securityTitle><conversionOrExercisePrice><value>19.4688</value></conversionOrExercisePrice><transactionDate><value>1988-08-08</value></transactionDate><transactionCoding><transactionFormType>4</transactionFormType><transactionCode>J</transactionCode><equitySwapInvolved>0</equitySwapInvolved><footnoteId id="F1"/></transactionCoding><transactionAmounts><transactionShares><value>0</value></transactionShares><transactionValue><value>19.4688</value></transactionValue><transactionAcquiredDisposedCode><value>A</value></transactionAcquiredDisposedCode></transactionAmounts><exerciseDate><value>2000-02-14</value></exerciseDate><expirationDate><value>2007-02-13</value></expirationDate><underlyingSecurity><underlyingSecurityTitle><value>Common Stock</value></underlyingSecurityTitle><underlyingSecurityShares><value>1000</value></underlyingSecurityShares></underlyingSecurity><postTransactionAmounts><sharesOwnedFollowingTransaction><value>1000</value></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>D</value></directOrIndirectOwnership><natureOfOwnership><value></value></natureOfOwnership></ownershipNature></derivativeSecurity><footnotes><footnote id="F1">Transaction code &amp;quot;J&amp;quot; does not represent a transaction. These lines are reporting securities owned as of the date of this filing.</footnote></footnotes><ownerSignature><signatureName>MICHAEL J. HERBERT as Attorney-In-Fact for EARL F. CHEIT</signatureName><signatureDate>2003-06-09</signatureDate></ownerSignature></ownershipDocument>

</XML>
</TEXT>
</DOCUMENT>
</SUBMISSION>
