<?xml version="1.0" encoding="us-ascii"?><InstanceReport xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"><Version>2.4.0.8</Version><ReportLongName>0015 - Disclosure - RESTRICTED STOCK</ReportLongName><DisplayLabelColumn>true</DisplayLabelColumn><ShowElementNames>false</ShowElementNames><RoundingOption /><HasEmbeddedReports>false</HasEmbeddedReports><Columns><Column FlagID="0"><Id>1</Id><IsAbstractGroupTitle>false</IsAbstractGroupTitle><LabelSeparator>

</LabelSeparator><CurrencyCode /><FootnoteIndexer /><hasSegments>false</hasSegments><hasScenarios>false</hasScenarios><MCU><KeyName /><CurrencySymbol /><contextRef><ContextID>From2013-01-01to2013-06-30</ContextID><EntitySchema>http://www.sec.gov/CIK</EntitySchema><EntityValue>0001031927</EntityValue><PeriodDisplayName /><PeriodType>duration</PeriodType><PeriodStartDate>2013-01-01T00:00:00</PeriodStartDate><PeriodEndDate>2013-06-30T00:00:00</PeriodEndDate><Segments /><Scenarios /></contextRef><UPS /><CurrencyCode /><OriginalCurrencyCode /></MCU><CurrencySymbol /><Labels><Label Key="CalendarSupplement" Id="0" Label="6 Months Ended" /><Label Key="Calendar" Id="1" Label="Jun. 30, 2013" /></Labels></Column></Columns><Rows><Row FlagID="0"><Id>1</Id><IsAbstractGroupTitle>true</IsAbstractGroupTitle><LabelSeparator>

</LabelSeparator><Level>1</Level><ElementName>ecte_NotesToFinancialStatementsAbstract</ElementName><ElementPrefix>ecte_</ElementPrefix><IsBaseElement>false</IsBaseElement><BalanceType>na</BalanceType><PeriodType>duration</PeriodType><IsReportTitle>false</IsReportTitle><IsSegmentTitle>false</IsSegmentTitle><IsCalendarTitle>false</IsCalendarTitle><IsEquityPrevioslyReportedAsRow>false</IsEquityPrevioslyReportedAsRow><IsEquityAdjustmentRow>false</IsEquityAdjustmentRow><IsBeginningBalance>false</IsBeginningBalance><IsEndingBalance>false</IsEndingBalance><IsReverseSign>false</IsReverseSign><FootnoteIndexer /><Cells><Cell FlagID="0" ContextID="" UnitID=""><Id>1</Id><IsNumeric>false</IsNumeric><IsRatio>false</IsRatio><DisplayZeroAsNone>false</DisplayZeroAsNone><NumericAmount>0</NumericAmount><RoundedNumericAmount>0</RoundedNumericAmount><NonNumbericText /><FootnoteIndexer /><CurrencyCode /><CurrencySymbol /><IsIndependantCurrency>false</IsIndependantCurrency><ShowCurrencySymbol>false</ShowCurrencySymbol><DisplayDateInUSFormat>false</DisplayDateInUSFormat></Cell></Cells><ElementDataType>xbrli:stringItemType</ElementDataType><SimpleDataType>string</SimpleDataType><IsTotalLabel>false</IsTotalLabel><UnitID>0</UnitID><Label>Notes to Financial Statements</Label></Row><Row FlagID="0"><Id>2</Id><IsAbstractGroupTitle>false</IsAbstractGroupTitle><LabelSeparator>

</LabelSeparator><Level>2</Level><ElementName>ecte_RestrictedStockTextBlock</ElementName><ElementPrefix>ecte_</ElementPrefix><IsBaseElement>false</IsBaseElement><BalanceType>na</BalanceType><PeriodType>duration</PeriodType><IsReportTitle>false</IsReportTitle><IsSegmentTitle>false</IsSegmentTitle><IsCalendarTitle>false</IsCalendarTitle><IsEquityPrevioslyReportedAsRow>false</IsEquityPrevioslyReportedAsRow><IsEquityAdjustmentRow>false</IsEquityAdjustmentRow><IsBeginningBalance>false</IsBeginningBalance><IsEndingBalance>false</IsEndingBalance><IsReverseSign>false</IsReverseSign><FootnoteIndexer /><Cells><Cell FlagID="0" ContextID="From2013-01-01to2013-06-30" UnitID=""><Id>1</Id><IsNumeric>false</IsNumeric><IsRatio>false</IsRatio><DisplayZeroAsNone>false</DisplayZeroAsNone><NumericAmount>0</NumericAmount><RoundedNumericAmount>0</RoundedNumericAmount><NonNumbericText>&lt;p style="font: 10pt/normal Times New Roman, Times, Serif; margin: 0; text-align: justify; text-indent: 9pt"&gt;&amp;#160;During the six
months ended June 30, 2013, the Company granted an aggregate of 38,638 restricted shares of Common Stock to certain officers, employees,
directors and consultants of the Company.&amp;#160;&amp;#160;The grants were issued pursuant to the 2008 Plan.&amp;#160;&amp;#160;The grant date
fair value of these restricted stock grants was approximately $250,316.&amp;#160;&amp;#160;Share-based compensation expense related to
restricted stock recognized in the six months ended June 30, 2013 and June 30, 2012 was approximately $313,000 and $29,000, respectively.&lt;/p&gt;

&lt;p style="font: 10pt/normal Times New Roman, Times, Serif; margin: 0; text-indent: 0.5in"&gt;&amp;#160;&lt;/p&gt;

&lt;p style="font: 10pt/normal Times New Roman, Times, Serif; margin: 0; text-align: justify; text-indent: 9pt"&gt;&amp;#160;A summary of
the Company&amp;#146;s nonvested restricted stock activity as of and for the six months ended June 30, 2013, is as follows:&lt;/p&gt;

&lt;p style="font: 10pt/normal Times New Roman, Times, Serif; margin: 0; text-align: justify; text-indent: 0.5in"&gt;&amp;#160;&lt;/p&gt;

&lt;table cellspacing="0" cellpadding="0" style="width: 100%; font: 10pt Calibri, Helvetica, Sans-Serif; border-collapse: collapse"&gt;
&lt;tr style="vertical-align: bottom"&gt;
    &lt;td style="border-bottom: black 1pt solid; line-height: 115%"&gt;&lt;font style="font: 10pt Times New Roman, Times, Serif; color: black"&gt;&lt;b&gt;Restricted Stock&lt;/b&gt;&lt;/font&gt;&lt;/td&gt;
    &lt;td style="line-height: 115%"&gt;&amp;#160;&lt;/td&gt;
    &lt;td colspan="2" style="border-bottom: black 1pt solid"&gt;
        &lt;p style="font: 10pt/normal Times New Roman, Times, Serif; margin: 0; text-indent: 0.5in"&gt;&amp;#160;&lt;/p&gt;
        &lt;p style="font: 10pt/normal Times New Roman, Times, Serif; margin: 0; text-indent: 0.5in"&gt;&amp;#160;&lt;/p&gt;
        &lt;p style="font: 10pt/normal Times New Roman, Times, Serif; margin: 0; text-align: center"&gt;&lt;b&gt;Shares&lt;/b&gt;&lt;/p&gt;&lt;/td&gt;
    &lt;td style="line-height: 115%"&gt;&amp;#160;&lt;/td&gt;
    &lt;td style="line-height: 115%"&gt;&amp;#160;&lt;/td&gt;
    &lt;td colspan="2" style="border-bottom: black 1pt solid"&gt;
        &lt;p style="font: 10pt/normal Times New Roman, Times, Serif; margin: 0; text-align: center"&gt;&lt;b&gt;Weighted-&lt;/b&gt;&lt;/p&gt;
        &lt;p style="font: 10pt/normal Times New Roman, Times, Serif; margin: 0; text-align: center"&gt;&lt;b&gt;Average&lt;/b&gt;&lt;/p&gt;
        &lt;p style="font: 10pt/normal Times New Roman, Times, Serif; margin: 0; text-align: center"&gt;&lt;b&gt;Grant-Date&lt;/b&gt;&lt;/p&gt;
        &lt;p style="font: 10pt/normal Times New Roman, Times, Serif; margin: 0; text-align: center"&gt;&lt;b&gt;Fair Value&lt;/b&gt;&lt;/p&gt;&lt;/td&gt;
    &lt;td style="line-height: 115%"&gt;&amp;#160;&lt;/td&gt;&lt;/tr&gt;
&lt;tr style="vertical-align: bottom; background-color: #CCEEFF"&gt;
    &lt;td style="width: 78%; text-indent: 12pt; line-height: 115%"&gt;&lt;font style="font: 10pt Times New Roman, Times, Serif; color: black"&gt;Nonvested at January 1, 2013&lt;/font&gt;&lt;/td&gt;
    &lt;td style="width: 1%; line-height: 115%"&gt;&amp;#160;&lt;/td&gt;
    &lt;td style="width: 1%; line-height: 115%"&gt;&amp;#160;&lt;/td&gt;
    &lt;td style="width: 8%; text-align: right; line-height: 115%"&gt;&lt;font style="font: 10pt Times New Roman, Times, Serif; color: black"&gt;316,044&lt;/font&gt;&lt;/td&gt;
    &lt;td style="width: 1%; line-height: 115%"&gt;&amp;#160;&lt;/td&gt;
    &lt;td style="width: 1%; line-height: 115%"&gt;&amp;#160;&lt;/td&gt;
    &lt;td style="width: 1%; line-height: 115%"&gt;&lt;font style="font: 10pt Times New Roman, Times, Serif; color: black"&gt;$&lt;/font&gt;&lt;/td&gt;
    &lt;td style="width: 8%; text-align: right; line-height: 115%"&gt;&lt;font style="font: 10pt Times New Roman, Times, Serif; color: black"&gt;16.60&lt;/font&gt;&lt;/td&gt;
    &lt;td style="width: 1%; line-height: 115%"&gt;&amp;#160;&lt;/td&gt;&lt;/tr&gt;
&lt;tr style="vertical-align: bottom; background-color: white"&gt;
    &lt;td style="padding-left: 0.25in; text-indent: 12pt; line-height: 115%"&gt;&lt;font style="font: 10pt Times New Roman, Times, Serif; color: black"&gt;Granted this period&lt;/font&gt;&lt;/td&gt;
    &lt;td style="line-height: 115%"&gt;&amp;#160;&lt;/td&gt;
    &lt;td style="line-height: 115%"&gt;&amp;#160;&lt;/td&gt;
    &lt;td style="text-align: right; line-height: 115%"&gt;&lt;font style="font: 10pt Times New Roman, Times, Serif; color: black"&gt;38,638&lt;/font&gt;&lt;/td&gt;
    &lt;td style="line-height: 115%"&gt;&amp;#160;&lt;/td&gt;
    &lt;td style="line-height: 115%"&gt;&amp;#160;&lt;/td&gt;
    &lt;td style="line-height: 115%"&gt;&amp;#160;&lt;/td&gt;
    &lt;td style="text-align: right; line-height: 115%"&gt;&lt;font style="font: 10pt Times New Roman, Times, Serif; color: black"&gt;6.48&lt;/font&gt;&lt;/td&gt;
    &lt;td style="line-height: 115%"&gt;&amp;#160;&lt;/td&gt;&lt;/tr&gt;
&lt;tr style="vertical-align: bottom; background-color: #CCEEFF"&gt;
    &lt;td style="padding-left: 0.25in; text-indent: 12pt; line-height: 115%"&gt;&lt;font style="font: 10pt Times New Roman, Times, Serif; color: black"&gt;Vested&lt;/font&gt;&lt;/td&gt;
    &lt;td style="line-height: 115%"&gt;&amp;#160;&lt;/td&gt;
    &lt;td style="line-height: 115%"&gt;&amp;#160;&lt;/td&gt;
    &lt;td style="text-align: right; line-height: 115%"&gt;&lt;font style="font: 10pt Times New Roman, Times, Serif; color: black"&gt;(22,953&lt;/font&gt;&lt;/td&gt;
    &lt;td style="line-height: 115%"&gt;&lt;font style="font: 10pt Times New Roman, Times, Serif; color: black"&gt;)&lt;/font&gt;&lt;/td&gt;
    &lt;td style="line-height: 115%"&gt;&amp;#160;&lt;/td&gt;
    &lt;td style="line-height: 115%"&gt;&amp;#160;&lt;/td&gt;
    &lt;td style="text-align: right; line-height: 115%"&gt;&lt;font style="font: 10pt Times New Roman, Times, Serif; color: black"&gt;19.75&lt;/font&gt;&lt;/td&gt;
    &lt;td style="line-height: 115%"&gt;&amp;#160;&lt;/td&gt;&lt;/tr&gt;
&lt;tr style="vertical-align: bottom; background-color: white"&gt;
    &lt;td style="padding-left: 0.25in; text-indent: 12pt; line-height: 115%"&gt;&lt;font style="font: 10pt Times New Roman, Times, Serif; color: black"&gt;Forfeited&lt;/font&gt;&lt;/td&gt;
    &lt;td style="line-height: 115%"&gt;&amp;#160;&lt;/td&gt;
    &lt;td style="border-bottom: black 1pt solid; line-height: 115%"&gt;&amp;#160;&lt;/td&gt;
    &lt;td style="border-bottom: black 1pt solid; text-align: right; line-height: 115%"&gt;&lt;font style="font: 10pt Times New Roman, Times, Serif; color: black"&gt;(24,500&lt;/font&gt;&lt;/td&gt;
    &lt;td style="line-height: 115%"&gt;&lt;font style="font: 10pt Times New Roman, Times, Serif; color: black"&gt;)&lt;/font&gt;&lt;/td&gt;
    &lt;td style="line-height: 115%"&gt;&amp;#160;&lt;/td&gt;
    &lt;td style="border-bottom: black 1pt solid; line-height: 115%"&gt;&amp;#160;&lt;/td&gt;
    &lt;td style="border-bottom: black 1pt solid; text-align: right; line-height: 115%"&gt;&lt;font style="font: 10pt Times New Roman, Times, Serif; color: black"&gt;9.94&lt;/font&gt;&lt;/td&gt;
    &lt;td style="line-height: 115%"&gt;&amp;#160;&lt;/td&gt;&lt;/tr&gt;
&lt;tr style="vertical-align: bottom; background-color: #CCEEFF"&gt;
    &lt;td style="text-indent: 12pt; line-height: 115%"&gt;&lt;font style="font: 10pt Times New Roman, Times, Serif; color: black"&gt;Nonvested at June 30, 2013&lt;/font&gt;&lt;/td&gt;
    &lt;td style="line-height: 115%"&gt;&amp;#160;&lt;/td&gt;
    &lt;td style="border-bottom: black 2.25pt double; line-height: 115%"&gt;&amp;#160;&lt;/td&gt;
    &lt;td style="border-bottom: black 2.25pt double; text-align: right; line-height: 115%"&gt;&lt;font style="font: 10pt Times New Roman, Times, Serif; color: black"&gt;307,229&lt;/font&gt;&lt;/td&gt;
    &lt;td style="line-height: 115%"&gt;&amp;#160;&lt;/td&gt;
    &lt;td style="line-height: 115%"&gt;&amp;#160;&lt;/td&gt;
    &lt;td style="border-bottom: black 2.25pt double; line-height: 115%"&gt;&lt;font style="font: 10pt Times New Roman, Times, Serif; color: black"&gt;$&lt;/font&gt;&lt;/td&gt;
    &lt;td style="border-bottom: black 2.25pt double; text-align: right; line-height: 115%"&gt;&lt;font style="font: 10pt Times New Roman, Times, Serif; color: black"&gt;15.62&lt;/font&gt;&lt;/td&gt;
    &lt;td style="line-height: 115%"&gt;&amp;#160;&lt;/td&gt;&lt;/tr&gt;
&lt;/table&gt;
&lt;p style="font: 10pt/normal Times New Roman, Times, Serif; margin: 0; text-indent: 0.5in"&gt;&amp;#160;&lt;/p&gt;

&lt;p style="font: 10pt/normal Times New Roman, Times, Serif; margin: 0; text-indent: 0.5in"&gt;Among the 307,229 shares of non-vested
restricted stock, the various vesting criteria include the following:&lt;/p&gt;

&lt;p style="font: 10pt/normal Times New Roman, Times, Serif; margin: 0"&gt;&amp;#160;&lt;/p&gt;

&lt;table cellpadding="0" cellspacing="0" style="width: 100%; font: 10pt/normal Times New Roman, Times, Serif; margin-top: 0; margin-bottom: 0"&gt;&lt;tr style="vertical-align: top"&gt;
&lt;td style="width: 0"&gt;&lt;/td&gt;&lt;td style="width: 45pt"&gt;&amp;#183;&lt;/td&gt;&lt;td&gt;165,460 shares of restricted stock vest upon the FDA approval of Symphony or the sale of the Company; and&lt;/td&gt;&lt;/tr&gt;&lt;/table&gt;

&lt;p style="font: 10pt/normal Times New Roman, Times, Serif; margin: 0; text-align: justify; text-indent: 0.5in"&gt;&lt;/p&gt;

&lt;table cellpadding="0" cellspacing="0" style="width: 100%; font: 10pt/normal Times New Roman, Times, Serif; margin-top: 0; margin-bottom: 0"&gt;&lt;tr style="vertical-align: top"&gt;
&lt;td style="width: 0"&gt;&lt;/td&gt;&lt;td style="width: 45pt"&gt;&amp;#183;&lt;/td&gt;&lt;td&gt;141,769 shares of restricted stock vest over one to four years, at each of the anniversary dates of the grants.&lt;/td&gt;&lt;/tr&gt;&lt;/table&gt;

&lt;p style="font: 10pt/normal Times New Roman, Times, Serif; margin: 0; text-align: justify; text-indent: 0.5in"&gt;&amp;#160;&lt;/p&gt;

&lt;p style="font: 10pt/normal Times New Roman, Times, Serif; margin: 0; text-align: justify; text-indent: 9pt"&gt;&amp;#160;As of June 30,
2013, there was approximately $1,658,000 of total unrecognized compensation expense related to non-vested share-based restricted
stock arrangements granted pursuant to the Company&amp;#146;s equity compensation plans that vest over time in the foreseeable future.
As of June 30, 2013, the Company cannot estimate the timing of completion of performance vesting requirements required by certain
of these restricted stock grant arrangements.&amp;#160;&amp;#160;Compensation expense related to these restricted share grants will be
recognized when the Company concludes that achievement of the performance vesting conditions is probable.&lt;/p&gt;

&lt;p style="font: 10pt/normal Times New Roman, Times, Serif; margin: 0"&gt;&amp;#160;&lt;/p&gt;</NonNumbericText><FootnoteIndexer /><CurrencyCode /><CurrencySymbol /><IsIndependantCurrency>false</IsIndependantCurrency><ShowCurrencySymbol>false</ShowCurrencySymbol><DisplayDateInUSFormat>false</DisplayDateInUSFormat></Cell></Cells><ElementDataType>nonnum:textBlockItemType</ElementDataType><SimpleDataType>na</SimpleDataType><ElementDefenition>RestrictedStockTextBlock</ElementDefenition><ElementReferences>No definition available.</ElementReferences><IsTotalLabel>false</IsTotalLabel><UnitID>0</UnitID><Label>Note 10. RESTRICTED STOCK</Label></Row></Rows><Footnotes /><IsEquityReport>false</IsEquityReport><ReportName>RESTRICTED STOCK</ReportName><MonetaryRoundingLevel>UnKnown</MonetaryRoundingLevel><SharesRoundingLevel>UnKnown</SharesRoundingLevel><PerShareRoundingLevel>UnKnown</PerShareRoundingLevel><ExchangeRateRoundingLevel>UnKnown</ExchangeRateRoundingLevel><HasCustomUnits>true</HasCustomUnits><IsEmbedReport>false</IsEmbedReport><IsMultiCurrency>false</IsMultiCurrency><ReportType>Sheet</ReportType><RoleURI>http://echotx.com/role/RestrictedStock</RoleURI><NumberOfCols>1</NumberOfCols><NumberOfRows>2</NumberOfRows></InstanceReport>
