<?xml version="1.0" encoding="us-ascii"?><InstanceReport xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema"><Version>2.2.0.25</Version><hasSegments>false</hasSegments><hasScenarios>false</hasScenarios><ReportLongName>00910 - Disclosure - Earnings Per Share</ReportLongName><DisplayLabelColumn>true</DisplayLabelColumn><ShowElementNames>false</ShowElementNames><RoundingOption /><HasEmbeddedReports>false</HasEmbeddedReports><Columns><Column><Id>1</Id><IsAbstractGroupTitle>false</IsAbstractGroupTitle><LabelColumn>false</LabelColumn><CurrencyCode>USD</CurrencyCode><FootnoteIndexer /><hasSegments>false</hasSegments><hasScenarios>false</hasScenarios><MCU><KeyName>5/1/2010 - 1/28/2011
USD ($)

USD ($) / shares
</KeyName><CurrencySymbol>$</CurrencySymbol><contextRef><ContextID>FROM_May01_2010_TO_Jan28_2011</ContextID><EntitySchema>http://www.sec.gov/CIK</EntitySchema><EntityValue>0000033769</EntityValue><PeriodDisplayName /><PeriodType>duration</PeriodType><PeriodStartDate>2010-05-01T00:00:00</PeriodStartDate><PeriodEndDate>2011-01-28T00:00:00</PeriodEndDate><Segments /><Scenarios /></contextRef><UPS><UnitProperty><UnitID>USD</UnitID><UnitType>Standard</UnitType><StandardMeasure><MeasureSchema>http://www.xbrl.org/2003/iso4217</MeasureSchema><MeasureValue>USD</MeasureValue><MeasureNamespace>iso4217</MeasureNamespace></StandardMeasure><Scale>0</Scale></UnitProperty><UnitProperty><UnitID>USDperShare</UnitID><UnitType>Divide</UnitType><NumeratorMeasure><MeasureSchema>http://www.xbrl.org/2003/iso4217</MeasureSchema><MeasureValue>USD</MeasureValue><MeasureNamespace>iso4217</MeasureNamespace></NumeratorMeasure><DenominatorMeasure><MeasureSchema>http://www.xbrl.org/2003/instance</MeasureSchema><MeasureValue>shares</MeasureValue><MeasureNamespace>xbrli</MeasureNamespace></DenominatorMeasure><Scale>0</Scale></UnitProperty></UPS><CurrencyCode>USD</CurrencyCode><OriginalCurrencyCode>USD</OriginalCurrencyCode></MCU><CurrencySymbol>$</CurrencySymbol><Labels><Label Id="1" Label="9 Months Ended" /><Label Id="2" Label="Jan. 28, 2011" /></Labels></Column></Columns><Rows><Row><Id>2</Id><IsAbstractGroupTitle>true</IsAbstractGroupTitle><Level>0</Level><ElementName>us-gaap_EarningsPerShareAbstract</ElementName><ElementPrefix>us-gaap</ElementPrefix><IsBaseElement>true</IsBaseElement><BalanceType>na</BalanceType><PeriodType>duration</PeriodType><ShortDefinition>No definition available.</ShortDefinition><IsReportTitle>false</IsReportTitle><IsSegmentTitle>false</IsSegmentTitle><IsSubReportEnd>false</IsSubReportEnd><IsCalendarTitle>false</IsCalendarTitle><IsTuple>false</IsTuple><IsEquityPrevioslyReportedAsRow>false</IsEquityPrevioslyReportedAsRow><IsEquityAdjustmentRow>false</IsEquityAdjustmentRow><IsBeginningBalance>false</IsBeginningBalance><IsEndingBalance>false</IsEndingBalance><IsReverseSign>false</IsReverseSign><PreferredLabelRole /><FootnoteIndexer /><Cells><Cell><Id>1</Id><IsNumeric>false</IsNumeric><IsRatio>false</IsRatio><DisplayZeroAsNone>false</DisplayZeroAsNone><NumericAmount>0</NumericAmount><RoundedNumericAmount>0</RoundedNumericAmount><NonNumbericText /><NonNumericTextHeader /><FootnoteIndexer /><CurrencyCode /><CurrencySymbol /><IsIndependantCurrency>false</IsIndependantCurrency><ShowCurrencySymbol>false</ShowCurrencySymbol><DisplayDateInUSFormat>false</DisplayDateInUSFormat><hasSegments>false</hasSegments><hasScenarios>false</hasScenarios></Cell></Cells><OriginalInstanceReportColumns /><Unit>Other</Unit><ElementDataType>xbrli:stringItemType</ElementDataType><SimpleDataType>string</SimpleDataType><ElementDefenition>No definition available.</ElementDefenition><IsTotalLabel>false</IsTotalLabel><IsEPS>false</IsEPS><Label>Footnote Earnings Per Share</Label></Row><Row><Id>3</Id><IsAbstractGroupTitle>false</IsAbstractGroupTitle><Level>0</Level><ElementName>us-gaap_EarningsPerShareTextBlock</ElementName><ElementPrefix>us-gaap</ElementPrefix><IsBaseElement>true</IsBaseElement><BalanceType>na</BalanceType><PeriodType>duration</PeriodType><ShortDefinition>No definition available.</ShortDefinition><IsReportTitle>false</IsReportTitle><IsSegmentTitle>false</IsSegmentTitle><IsSubReportEnd>false</IsSubReportEnd><IsCalendarTitle>false</IsCalendarTitle><IsTuple>false</IsTuple><IsEquityPrevioslyReportedAsRow>false</IsEquityPrevioslyReportedAsRow><IsEquityAdjustmentRow>false</IsEquityAdjustmentRow><IsBeginningBalance>false</IsBeginningBalance><IsEndingBalance>false</IsEndingBalance><IsReverseSign>false</IsReverseSign><PreferredLabelRole /><FootnoteIndexer /><Cells><Cell><Id>1</Id><IsNumeric>false</IsNumeric><IsRatio>false</IsRatio><DisplayZeroAsNone>false</DisplayZeroAsNone><NumericAmount>0</NumericAmount><RoundedNumericAmount>0</RoundedNumericAmount><NonNumbericText>&lt;p style='margin-top:0pt; margin-bottom:0pt'&gt;&lt;font style="font-family:Times New Roman;font-size:10.5pt;margin-left:0px;"&gt;2.&lt;/font&gt;&lt;font style="font-family:Times New Roman;font-size:10.5pt;"&gt; &lt;/font&gt;&lt;font style="font-family:Times New Roman;font-size:10.5pt;text-decoration:underline;"&gt;Earnings Per Share&lt;/font&gt;&lt;/p&gt;&lt;p style='margin-top:0pt; margin-bottom:0pt'&gt;&lt;font style="font-family:Times New Roman;font-size:11pt;margin-left:0px;"&gt;             &lt;/font&gt;&lt;font style="font-family:Times New Roman;font-size:10.5pt;"&gt;Basic earnings-per-share computations are based on the weighted-average number of shares of common stock outstanding during the period presented.  Diluted earnings-per-share calculations reflect the assumed exercise and conversion of employee stock options.&lt;/font&gt;&lt;/p&gt;&lt;p style='margin-top:0pt; margin-bottom:0pt'&gt;&lt;font style="font-family:Times New Roman;font-size:11pt;margin-left:0px;"&gt;            &lt;/font&gt;&lt;font style="font-family:Times New Roman;font-size:10.5pt;"&gt;The numerator in calculating both basic and diluted earnings per share for each period was net income. The denominator was based on the following weighted-average number of common shares outstanding:&lt;/font&gt;&lt;/p&gt;&lt;p style='margin-top: 0pt; margin-bottom: 0pt;'&gt;&lt;/p&gt;&lt;div&gt;&lt;table style="border-collapse:collapse;margin-top:20px;"&gt;&lt;tr style="height: 20px"&gt;&lt;td   style="width: 276px; text-align:left;border-color:#000000;min-width:276px;"&gt;&amp;#160;&lt;/td&gt;&lt;td colspan="7"  style="width: 396px; text-align:center;border-color:#000000;min-width:396px;"&gt;&lt;font style="FONT-FAMILY: Times New Roman;FONT-SIZE: 10.5pt;COLOR: #000000;TEXT-ALIGN: center;"&gt;(In thousands)&lt;/font&gt;&lt;/td&gt;&lt;/tr&gt;&lt;tr style="height: 20px"&gt;&lt;td   style="width: 276px; text-align:left;border-color:#000000;min-width:276px;"&gt;&amp;#160;&lt;/td&gt;&lt;td colspan="3"  style="width: 192px; border-bottom-style:solid;border-bottom-width:1px;text-align:center;border-color:#000000;min-width:192px;"&gt;&lt;font style="FONT-FAMILY: Times New Roman;FONT-SIZE: 10.5pt;COLOR: #000000;TEXT-ALIGN: center;"&gt;Three Months Ended&lt;/font&gt;&lt;/td&gt;&lt;td   style="width: 12px; text-align:left;border-color:#000000;min-width:12px;"&gt;&amp;#160;&lt;/td&gt;&lt;td colspan="3"  style="width: 192px; border-bottom-style:solid;border-bottom-width:1px;text-align:center;border-color:#000000;min-width:192px;"&gt;&lt;font style="FONT-FAMILY: Times New Roman;FONT-SIZE: 10.5pt;COLOR: #000000;TEXT-ALIGN: center;"&gt;Nine Months Ended&lt;/font&gt;&lt;/td&gt;&lt;/tr&gt;&lt;tr style="height: 20px"&gt;&lt;td   style="width: 276px; text-align:left;border-color:#000000;min-width:276px;"&gt;&amp;#160;&lt;/td&gt;&lt;td   style="width: 90px; border-top-style:solid;border-top-width:1px;border-bottom-style:solid;border-bottom-width:1px;text-align:center;border-color:#000000;min-width:90px;"&gt;&lt;font style="FONT-FAMILY: Times New Roman;FONT-SIZE: 10.5pt;COLOR: #000000;TEXT-ALIGN: center;"&gt;Jan. 28, 2011&lt;/font&gt;&lt;/td&gt;&lt;td   style="width: 12px; border-top-style:solid;border-top-width:1px;text-align:left;border-color:#000000;min-width:12px;"&gt;&amp;#160;&lt;/td&gt;&lt;td   style="width: 90px; border-top-style:solid;border-top-width:1px;border-bottom-style:solid;border-bottom-width:1px;text-align:center;border-color:#000000;min-width:90px;"&gt;&lt;font style="FONT-FAMILY: Times New Roman;FONT-SIZE: 10.5pt;COLOR: #000000;TEXT-ALIGN: center;"&gt;Jan. 22, 2010&lt;/font&gt;&lt;/td&gt;&lt;td   style="width: 12px; text-align:left;border-color:#000000;min-width:12px;"&gt;&amp;#160;&lt;/td&gt;&lt;td   style="width: 90px; border-top-style:solid;border-top-width:1px;border-bottom-style:solid;border-bottom-width:1px;text-align:center;border-color:#000000;min-width:90px;"&gt;&lt;font style="FONT-FAMILY: Times New Roman;FONT-SIZE: 10.5pt;COLOR: #000000;TEXT-ALIGN: center;"&gt;Jan. 28, 2011&lt;/font&gt;&lt;/td&gt;&lt;td   style="width: 12px; border-top-style:solid;border-top-width:1px;text-align:right;border-color:#000000;min-width:12px;"&gt;&amp;#160;&lt;/td&gt;&lt;td   style="width: 90px; border-top-style:solid;border-top-width:1px;border-bottom-style:solid;border-bottom-width:1px;text-align:center;border-color:#000000;min-width:90px;"&gt;&lt;font style="FONT-FAMILY: Times New Roman;FONT-SIZE: 10.5pt;COLOR: #000000;TEXT-ALIGN: center;"&gt;Jan. 22, 2010&lt;/font&gt;&lt;/td&gt;&lt;/tr&gt;&lt;tr style="height: 20px"&gt;&lt;td   style="width: 276px; text-align:left;border-color:#000000;min-width:276px;"&gt;&lt;font style="FONT-FAMILY: Times New Roman;FONT-SIZE: 10.5pt;COLOR: #000000;"&gt;Basic&lt;/font&gt;&lt;/td&gt;&lt;td   style="width: 90px; border-top-style:solid;border-top-width:1px;text-align:right;border-color:#000000;min-width:90px;"&gt;&lt;font style="FONT-FAMILY: Times New Roman;FONT-SIZE: 10.5pt;COLOR: #000000;"&gt; 30,258&lt;/font&gt;&lt;/td&gt;&lt;td   style="width: 12px; text-align:left;border-color:#000000;min-width:12px;"&gt;&amp;#160;&lt;/td&gt;&lt;td   style="width: 90px; border-top-style:solid;border-top-width:1px;text-align:right;border-color:#000000;min-width:90px;"&gt;&lt;font style="FONT-FAMILY: Times New Roman;FONT-SIZE: 10.5pt;COLOR: #000000;"&gt; 30,843&lt;/font&gt;&lt;/td&gt;&lt;td   style="width: 12px; text-align:left;border-color:#000000;min-width:12px;"&gt;&amp;#160;&lt;/td&gt;&lt;td   style="width: 90px; border-top-style:solid;border-top-width:1px;text-align:right;border-color:#000000;min-width:90px;"&gt;&lt;font style="FONT-FAMILY: Times New Roman;FONT-SIZE: 10.5pt;COLOR: #000000;TEXT-ALIGN: right;"&gt; 30,348&lt;/font&gt;&lt;/td&gt;&lt;td   style="width: 12px; text-align:right;border-color:#000000;min-width:12px;"&gt;&amp;#160;&lt;/td&gt;&lt;td   style="width: 90px; border-top-style:solid;border-top-width:1px;text-align:right;border-color:#000000;min-width:90px;"&gt;&lt;font style="FONT-FAMILY: Times New Roman;FONT-SIZE: 10.5pt;COLOR: #000000;TEXT-ALIGN: right;"&gt; 30,896&lt;/font&gt;&lt;/td&gt;&lt;/tr&gt;&lt;tr style="height: 20px"&gt;&lt;td   style="width: 276px; text-align:left;border-color:#000000;min-width:276px;"&gt;&lt;font style="FONT-FAMILY: Times New Roman;FONT-SIZE: 10.5pt;COLOR: #000000;"&gt;Effect of dilutive stock options&lt;/font&gt;&lt;/td&gt;&lt;td   style="width: 90px; border-bottom-style:solid;border-bottom-width:1px;text-align:right;border-color:#000000;min-width:90px;"&gt;&lt;font style="FONT-FAMILY: Times New Roman;FONT-SIZE: 10.5pt;COLOR: #000000;"&gt; 146&lt;/font&gt;&lt;/td&gt;&lt;td   style="width: 12px; text-align:left;border-color:#000000;min-width:12px;"&gt;&amp;#160;&lt;/td&gt;&lt;td   style="width: 90px; border-bottom-style:solid;border-bottom-width:1px;text-align:right;border-color:#000000;min-width:90px;"&gt;&lt;font style="FONT-FAMILY: Times New Roman;FONT-SIZE: 10.5pt;COLOR: #000000;"&gt; 93&lt;/font&gt;&lt;/td&gt;&lt;td   style="width: 12px; text-align:left;border-color:#000000;min-width:12px;"&gt;&amp;#160;&lt;/td&gt;&lt;td   style="width: 90px; border-bottom-style:solid;border-bottom-width:1px;text-align:right;border-color:#000000;min-width:90px;"&gt;&lt;font style="FONT-FAMILY: Times New Roman;FONT-SIZE: 10.5pt;COLOR: #000000;TEXT-ALIGN: right;"&gt; 89&lt;/font&gt;&lt;/td&gt;&lt;td   style="width: 12px; text-align:right;border-color:#000000;min-width:12px;"&gt;&amp;#160;&lt;/td&gt;&lt;td   style="width: 90px; border-bottom-style:solid;border-bottom-width:1px;text-align:right;border-color:#000000;min-width:90px;"&gt;&lt;font style="FONT-FAMILY: Times New Roman;FONT-SIZE: 10.5pt;COLOR: #000000;TEXT-ALIGN: right;"&gt; 98&lt;/font&gt;&lt;/td&gt;&lt;/tr&gt;&lt;tr style="height: 20px"&gt;&lt;td   style="width: 276px; text-align:left;border-color:#000000;min-width:276px;"&gt;&lt;font style="FONT-FAMILY: Times New Roman;FONT-SIZE: 10.5pt;COLOR: #000000;"&gt;Diluted&lt;/font&gt;&lt;/td&gt;&lt;td   style="width: 90px; border-top-style:solid;border-top-width:1px;border-bottom-style:double;border-bottom-width:3px;text-align:right;border-color:#000000;min-width:90px;"&gt;&lt;font style="FONT-FAMILY: Times New Roman;FONT-SIZE: 10.5pt;COLOR: #000000;"&gt; 30,404&lt;/font&gt;&lt;/td&gt;&lt;td   style="width: 12px; text-align:left;border-color:#000000;min-width:12px;"&gt;&amp;#160;&lt;/td&gt;&lt;td   style="width: 90px; border-top-style:solid;border-top-width:1px;border-bottom-style:double;border-bottom-width:3px;text-align:right;border-color:#000000;min-width:90px;"&gt;&lt;font style="FONT-FAMILY: Times New Roman;FONT-SIZE: 10.5pt;COLOR: #000000;"&gt; 30,936&lt;/font&gt;&lt;/td&gt;&lt;td   style="width: 12px; text-align:left;border-color:#000000;min-width:12px;"&gt;&amp;#160;&lt;/td&gt;&lt;td   style="width: 90px; border-top-style:solid;border-top-width:1px;border-bottom-style:double;border-bottom-width:3px;text-align:right;border-color:#000000;min-width:90px;"&gt;&lt;font style="FONT-FAMILY: Times New Roman;FONT-SIZE: 10.5pt;COLOR: #000000;TEXT-ALIGN: right;"&gt; 30,437&lt;/font&gt;&lt;/td&gt;&lt;td   style="width: 12px; text-align:right;border-color:#000000;min-width:12px;"&gt;&amp;#160;&lt;/td&gt;&lt;td   style="width: 90px; border-top-style:solid;border-top-width:1px;border-bottom-style:double;border-bottom-width:3px;text-align:right;border-color:#000000;min-width:90px;"&gt;&lt;font style="FONT-FAMILY: Times New Roman;FONT-SIZE: 10.5pt;COLOR: #000000;TEXT-ALIGN: right;"&gt; 30,994&lt;/font&gt;&lt;/td&gt;&lt;/tr&gt;&lt;/table&gt;&lt;/div&gt;</NonNumbericText><NonNumericTextHeader>2. Earnings Per Share             Basic earnings-per-share computations are based on the weighted-average number of shares of common stock outstanding during</NonNumericTextHeader><FootnoteIndexer /><CurrencyCode /><CurrencySymbol /><IsIndependantCurrency>false</IsIndependantCurrency><ShowCurrencySymbol>false</ShowCurrencySymbol><DisplayDateInUSFormat>false</DisplayDateInUSFormat><hasSegments>false</hasSegments><hasScenarios>false</hasScenarios></Cell></Cells><OriginalInstanceReportColumns /><Unit>Other</Unit><ElementDataType>us-types:textBlockItemType</ElementDataType><SimpleDataType>string</SimpleDataType><ElementDefenition>This element may be used to capture the complete disclosure pertaining to an entity's earnings per share.</ElementDefenition><ElementReferences>Reference 1: http://www.xbrl.org/2003/role/presentationRef
 -Publisher FASB
 -Name Statement of Financial Accounting Standard (FAS)
 -Number 128
 -Paragraph 40

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