diff --git a/msbuild/Xamarin.iOS.Tasks.Core/Xamarin.iOS.Common.targets b/msbuild/Xamarin.iOS.Tasks.Core/Xamarin.iOS.Common.targets
index cfa7bb0e9726..b453044c3668 100644
--- a/msbuild/Xamarin.iOS.Tasks.Core/Xamarin.iOS.Common.targets
+++ b/msbuild/Xamarin.iOS.Tasks.Core/Xamarin.iOS.Common.targets
@@ -302,11 +302,13 @@ Copyright (C) 2013-2016 Xamarin. All rights reserved.
 			_EmbedMobileProvision;
 			_CodesignNativeLibraries;
 			_CodesignFrameworks;
+			_CodesignAppExtensions;
 		</_CodesignAppBundleDependsOn>
 
 		<_CoreCodesignDependsOn>
 			_CodesignNativeLibraries;
 			_CodesignFrameworks;
+			_CodesignAppExtensions;
 			_CodesignAppBundle;
 			_CodesignVerify;
 		</_CoreCodesignDependsOn>
@@ -342,6 +344,7 @@ Copyright (C) 2013-2016 Xamarin. All rights reserved.
 
 	<Target Name="_CleanAppBundle" Condition="'$(_CanOutputAppBundle)' == 'true'" DependsOnTargets="_GenerateBundleName">
 		<RemoveDir SessionId="$(BuildSessionId)" Condition="'$(IsMacEnabled)' == 'true'" Directories="$(_AppBundlePath)" />
+		<Delete SessionId="$(BuildSessionId)" Condition="'$(IsMacEnabled)' == 'true' And '$(IsAppExtension)' == 'true'" Files="$(AppBundleDir)\..\codesign.items" />
 	</Target>
 
 	<Target Name="_CleanUploaded" Condition="'$(_CanOutputAppBundle)' == 'true'" DependsOnTargets="_GenerateBundleName">
@@ -1530,7 +1533,7 @@ Copyright (C) 2013-2016 Xamarin. All rights reserved.
 	<!-- Note: Always codesign *.dylibs even for Simulator builds. We use $(_CanOutputAppBundle) because dylibs can exist in app extensions as well. -->
 	<Target Name="_CodesignNativeLibraries" Condition="'$(_CanOutputAppBundle)' == 'true'" DependsOnTargets="_DetectSigningIdentity">
 		<Codesign
-			Condition="'$(IsMacEnabled)' == 'true' And '@(_NativeLibrary)' != '' And '$(_CodeSigningKey)' != ''"
+			Condition="'$(IsMacEnabled)' == 'true' And '@(_NativeLibrary)' != '' And '$(_CodeSigningKey)' != '' And '$(IsAppExtension)' == 'false'"
 			SessionId="$(BuildSessionId)"
 			ToolExe="$(CodesignExe)"
 			ToolPath="$(CodesignPath)"
@@ -1546,7 +1549,7 @@ Copyright (C) 2013-2016 Xamarin. All rights reserved.
 
 	<Target Name="_CodesignFrameworks" Condition="'$(_CanOutputAppBundle)' == 'true'" DependsOnTargets="_DetectSigningIdentity;_CollectFrameworks">
 		<Codesign
-			Condition="'$(IsMacEnabled)' == 'true' And '@(_Frameworks)' != '' And '$(_CodeSigningKey)' != ''"
+			Condition="'$(IsMacEnabled)' == 'true' And '@(_Frameworks)' != '' And '$(_CodeSigningKey)' != '' And '$(IsAppExtension)' == 'false'"
 			SessionId="$(BuildSessionId)"
 			ToolExe="$(CodesignExe)"
 			ToolPath="$(CodesignPath)"
@@ -1560,10 +1563,74 @@ Copyright (C) 2013-2016 Xamarin. All rights reserved.
 		</Codesign>
 	</Target>
 
-	<Target Name="_CodesignAppBundle" Condition="'$(_RequireCodeSigning)' == 'true'" DependsOnTargets="$(_CodesignAppBundleDependsOn)">
+	<Target Name="_ReadAppExtensionCodesignProperties" DependsOnTargets="_CopyAppExtensionsToBundle">
+		<ReadItemsFromFile File="%(_ResolvedAppExtensionReferences.Identity)\..\codesign.items" Condition="Exists('%(_ResolvedAppExtensionReferences.Identity)\..\codesign.items')">
+			<Output TaskParameter="Items" ItemName="_AppExtensionCodesignProperties" />
+		</ReadItemsFromFile>
+	</Target>
+
+	<Target Name="_CodesignAppExtensions" Condition="'$(_RequireCodeSigning)' == 'true' And '$(IsAppExtension)' == 'false' And ('$(OutputType)' == 'Exe' Or '$(IsWatchApp)' == 'true')" DependsOnTargets="_DetectSigningIdentity;_ReadAppExtensionCodesignProperties">
 		<Codesign
 			SessionId="$(BuildSessionId)"
+			Condition="'$(IsMacEnabled)' == 'true' And '@(_AppExtensionCodesignProperties)' != ''"
+			ToolExe="$(CodesignExe)"
+			ToolPath="$(CodesignPath)"
+			CodesignAllocate="%(_AppExtensionCodesignProperties.CodesignAllocate)"
+			DisableTimestamp="%(_AppExtensionCodesignProperties.DisableTimestamp)"
+			Keychain="%(_AppExtensionCodesignProperties.Keychain)"
+			Entitlements="%(_AppExtensionCodesignProperties.Entitlements)"
+			ResourceRules="%(_AppExtensionCodesignProperties.ResourceRules)"
+			Resource="$(_AppBundlePath)PlugIns\%(_AppExtensionCodesignProperties.Identity)"
+			SigningKey="%(_AppExtensionCodesignProperties.SigningKey)"
+			ExtraArgs="%(_AppExtensionCodesignProperties.ExtraArgs)"
+			>
+		</Codesign>
+
+		<Touch
+			SessionId="$(BuildSessionId)"
+			Condition="'$(IsMacEnabled)' == 'true' And '$(_RequireCodeSigning)' == 'true' And Exists ('$(AppBundleDir)\..\%(_AppExtensionCodesignProperties.Identity).dSYM\Contents\Info.plist')"
+			Files="$(AppBundleDir)\..\%(_AppExtensionCodesignProperties.Identity).dSYM\Contents\Info.plist"
+		/>
+	</Target>
+
+	<Target Name="_PrepareCodesignAppBundle" Condition="'$(_RequireCodeSigning)' == 'true' And '$(IsAppExtension)' == 'true'">
+		<!-- For App Extensions, we delay running codesign until it has been copied into the main app bundle... -->
+
+		<PropertyGroup>
+			<_AppBundleFileName>$([System.IO.Path]::GetFileName('$(AppBundleDir)'))</_AppBundleFileName>
+
+			<_EntitlementsFullPath>$([System.IO.Path]::GetFullPath('$(DeviceSpecificIntermediateOutputPath)Entitlements.xcent'))</_EntitlementsFullPath>
+
+			<_ResourceRulesFullPath></_ResourceRulesFullPath>
+			<_ResourceRulesFullPath Condition="'$(_PreparedResourceRules)' != ''">$([System.IO.Path]::GetFullPath('$(_PreparedResourceRules)'))</_ResourceRulesFullPath>
+		</PropertyGroup>
+
+		<ItemGroup>
+			<_AppExtensionCodesignProperties Include="$(_AppBundleFileName)">
+				<CodesignAllocate>$(_CodesignAllocate)</CodesignAllocate>
+				<DisableTimestamp>$(_SdkIsSimulator)</DisableTimestamp>
+				<Entitlements>$(_EntitlementsFullPath)</Entitlements>
+				<ResourceRules>$(_ResourceRulesFullPath)</ResourceRules>
+				<Keychain>$(CodesignKeychain)</Keychain>
+				<SigningKey>$(_CodeSigningKey)</SigningKey>
+				<ExtraArgs>$(CodesignExtraArgs)</ExtraArgs>
+			</_AppExtensionCodesignProperties>
+		</ItemGroup>
+
+		<WriteItemsToFile
 			Condition="'$(IsMacEnabled)' == 'true'"
+			Items="@(_AppExtensionCodesignProperties)"
+			ItemName="_AppExtensionCodesignProperties"
+			File="$(AppBundleDir)\..\codesign.items"
+			IncludeMetadata="true"
+			Overwrite="true"
+		/>
+	</Target>
+
+	<Target Name="_CodesignAppBundle" Condition="'$(_RequireCodeSigning)' == 'true'" DependsOnTargets="$(_CodesignAppBundleDependsOn);_PrepareCodesignAppBundle">
+		<Codesign
+			SessionId="$(BuildSessionId)"
+			Condition="'$(IsMacEnabled)' == 'true' And '$(IsAppExtension)' == 'false'"
 			ToolExe="$(CodesignExe)"
 			ToolPath="$(CodesignPath)"
 			CodesignAllocate="$(_CodesignAllocate)"
@@ -1579,12 +1646,12 @@ Copyright (C) 2013-2016 Xamarin. All rights reserved.
 
 		<Touch
 			SessionId="$(BuildSessionId)"
-			Condition="'$(IsMacEnabled)' == 'true' And '$(_RequireCodeSigning)' == 'true' And Exists ('$(AppBundleDir).dSYM\Contents\Info.plist')"
+			Condition="'$(IsMacEnabled)' == 'true' And '$(_RequireCodeSigning)' == 'true' And '$(IsAppExtension)' == 'false' And Exists ('$(AppBundleDir).dSYM\Contents\Info.plist')"
 			Files="$(AppBundleDir).dSYM\Contents\Info.plist"
 		/>
 	</Target>
 
-	<Target Name="_CodesignVerify" Condition="'$(_RequireCodeSigning)' == 'true'" DependsOnTargets="_CodesignAppBundle">
+	<Target Name="_CodesignVerify" Condition="'$(_RequireCodeSigning)' == 'true' And '$(IsAppExtension)' == 'false'" DependsOnTargets="_CodesignAppBundle">
 		<CodesignVerify
 			SessionId="$(BuildSessionId)"
 			Condition="'$(IsMacEnabled)' == 'true'"