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

    <schemaVersion>X0306</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2012-12-11</periodOfReport>

    <issuer>
        <issuerCik>0000737758</issuerCik>
        <issuerName>TORO CO</issuerName>
        <issuerTradingSymbol>TTC</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001382452</rptOwnerCik>
            <rptOwnerName>Happe Michael J</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>8111 LYNDALE AVENUE SOUTH</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>BLOOMINGTON</rptOwnerCity>
            <rptOwnerState>MN</rptOwnerState>
            <rptOwnerZipCode>55420-1196</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isOfficer>1</isOfficer>
            <officerTitle>Group VP, Res. &amp; Cont.</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Performance Share Units</value>
            </securityTitle>
            <transactionDate>
                <value>2012-12-11</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness></transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>9000</value>
                    <footnoteId id="F1"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>11328.375</value>
                    <footnoteId id="F2"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>6140.326</value>
                    <footnoteId id="F3"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>10893.918</value>
                    <footnoteId id="F4"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>The Toro Company Investment, Savings &amp; ESOP</value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
    </nonDerivativeTable>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>Non-Qualified Stock Option</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>42.06</value>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2012-12-11</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness></transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>16800</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <footnoteId id="F5"/>
            </exerciseDate>
            <expirationDate>
                <value>2022-12-11</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>16800</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>16800</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeTransaction>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">Represents the payout of a Performance Share Award for the Fiscal 2010 to Fiscal 2012 Performance Period under The Toro Company Performance Share Plan, as approved by the registrant's Compensation &amp; Human Resources Committee of its Board of Directors on December 11, 2012. The reporting person has deferred the payout of his Performance Share Award under The Toro Company Deferred Compensation Plan for Officers (the &quot;Deferred Plan&quot;) and, accordingly, the reporting person's Performance Share Award is paid in performance share units under the Deferred Plan.</footnote>
        <footnote id="F2">On June 29, 2012, the common stock of the issuer split two-for-one (the &quot;Stock Split&quot;), resulting in the reporting person's ownership of 1,160.994 additional performance share units.  Also includes 6.387 post-split performance share units acquired by the reporting person under the dividend reinvestment feature of the Deferred Plan since the date of his last report. All future Form 4 and 5 filings made by the reporting person will include adjustments, as necessary, to reflect the Stock Split.</footnote>
        <footnote id="F3">Includes ownership of 1,509.075 additional shares of common stock subject to restriction and 1,552.654 additional shares of common stock not subject to restriction acquired as a result of the Stock Split. Also includes 8.314 post-split dividend reinvestment shares acquired by the reporting person under The Toro Company Dividend Reinvestment Plan (&quot;DRIP&quot;) from dividends paid on the restricted stock and 8.554 shares of post-split common stock not subject to restriction acquired under the DRIP since the date of his last report. 3,026.464 shares of restricted stock and related DRIP shares vest in full on the third anniversary of the date of grant, which was March 20, 2012.</footnote>
        <footnote id="F4">Includes the following shares of common stock acquired by the reporting person since the date of his last report: 29.842 post-split shares acquired under the dividend reinvestment feature of The Toro Company Investment, Savings &amp; ESOP (&quot;IS&amp;ESOP&quot;); 180.533 post-split shares acquired through regular individual and issuer matching contributions to  the IS&amp;ESOP; and 5,332.121 additional shares acquired as a result of the Stock Split.</footnote>
        <footnote id="F5">The option vests in three equal annual installments commencing on the first anniversary of the date of grant.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>/s/ Nancy A. McGrath, Attorney-in-Fact</signatureName>
        <signatureDate>2012-12-13</signatureDate>
    </ownerSignature>
</ownershipDocument>
