diff --git a/src/StaticWebAssetsSdk/Targets/Microsoft.NET.Sdk.StaticWebAssets.Publish.targets b/src/StaticWebAssetsSdk/Targets/Microsoft.NET.Sdk.StaticWebAssets.Publish.targets
index f5d5181b2ebb..0b392f857100 100644
--- a/src/StaticWebAssetsSdk/Targets/Microsoft.NET.Sdk.StaticWebAssets.Publish.targets
+++ b/src/StaticWebAssetsSdk/Targets/Microsoft.NET.Sdk.StaticWebAssets.Publish.targets
@@ -200,6 +200,7 @@ Copyright (c) .NET Foundation. All rights reserved.
     <ItemGroup>
       <_PublishStaticWebAssetsCopyAlways Include="@(_PublishStaticWebAssetsTargetPath)" Condition="'%(CopyToPublishDirectory)' == 'Always'" />
       <_PublishStaticWebAssetsPreserveNewest Include="@(_PublishStaticWebAssetsTargetPath)" Condition="'%(CopyToPublishDirectory)' == 'PreserveNewest'" />
+      <_PublishStaticWebAssetsIfDifferent Include="@(_PublishStaticWebAssetsTargetPath)" Condition="'%(CopyToPublishDirectory)' == 'IfDifferent'" />
     </ItemGroup>
 
   </Target>
@@ -207,7 +208,8 @@ Copyright (c) .NET Foundation. All rights reserved.
   <Target Name="_PublishCopyStaticWebAssetsPreserveNewest"
     Inputs="@(_PublishStaticWebAssetsPreserveNewest)"
     Outputs="@(_PublishStaticWebAssetsPreserveNewest->'$(PublishDir)%(TargetPath)')"
-    AfterTargets="_SplitPublishStaticWebAssetsByCopyOptions">
+    AfterTargets="_SplitPublishStaticWebAssetsByCopyOptions"
+    Condition=" '@(_PublishStaticWebAssetsPreserveNewest)' != '' ">
 
     <Copy SourceFiles="@(_PublishStaticWebAssetsPreserveNewest)"
       DestinationFiles="@(_PublishStaticWebAssetsPreserveNewest->'$(PublishDir)%(TargetPath)')"
@@ -224,7 +226,8 @@ Copyright (c) .NET Foundation. All rights reserved.
   </Target>
 
   <Target Name="_PublishCopyStaticWebAssetsAlways"
-    AfterTargets="_SplitPublishStaticWebAssetsByCopyOptions">
+    AfterTargets="_SplitPublishStaticWebAssetsByCopyOptions"
+    Condition=" '@(_PublishStaticWebAssetsCopyAlways)' != '' ">
 
     <Copy SourceFiles="@(_PublishStaticWebAssetsCopyAlways)"
       DestinationFiles="@(_PublishStaticWebAssetsCopyAlways->'$(PublishDir)%(TargetPath)')"
@@ -239,6 +242,28 @@ Copyright (c) .NET Foundation. All rights reserved.
     </Copy>
 
   </Target>
+  
+  <Target Name="_PublishCopyStaticWebAssetsIfDifferent"
+    AfterTargets="_SplitPublishStaticWebAssetsByCopyOptions"
+    Condition=" '@(_PublishStaticWebAssetsIfDifferent)' != '' ">
+
+    <!--
+        Using SkipUnchangedFiles="true" because we want only differing files.
+    -->
+    <Copy SourceFiles="@(_PublishStaticWebAssetsIfDifferent)"
+      DestinationFiles="@(_PublishStaticWebAssetsIfDifferent->'$(PublishDir)%(TargetPath)')"
+      SkipUnchangedFiles="true"
+      OverwriteReadOnlyFiles="$(OverwriteReadOnlyFiles)"
+      Retries="$(CopyRetryCount)"
+      RetryDelayMilliseconds="$(CopyRetryDelayMilliseconds)"
+      UseHardlinksIfPossible="$(CreateHardLinksForPublishFilesIfPossible)"
+      UseSymboliclinksIfPossible="$(CreateSymbolicLinksForPublishFilesIfPossible)">
+
+      <Output TaskParameter="DestinationFiles" ItemName="FileWrites"/>
+
+    </Copy>
+
+  </Target>
 
   <Target Name="CopyStaticWebAssetsEndpointsManifest" DependsOnTargets="GenerateStaticWebAssetsPublishManifest"
     AfterTargets="CopyStaticWebAssetsToPublishDirectory">
diff --git a/src/StaticWebAssetsSdk/Targets/Microsoft.NET.Sdk.StaticWebAssets.targets b/src/StaticWebAssetsSdk/Targets/Microsoft.NET.Sdk.StaticWebAssets.targets
index 0fb3afa2fbc2..c3e5fad9ab49 100644
--- a/src/StaticWebAssetsSdk/Targets/Microsoft.NET.Sdk.StaticWebAssets.targets
+++ b/src/StaticWebAssetsSdk/Targets/Microsoft.NET.Sdk.StaticWebAssets.targets
@@ -498,6 +498,7 @@ Copyright (c) .NET Foundation. All rights reserved.
     <ItemGroup>
       <_BuildStaticWebAssetsCopyAlways Include="@(_BuildStaticWebAssetsTargetPath)" Condition="'%(CopyToOutputDirectory)' == 'Always'" />
       <_BuildStaticWebAssetsPreserveNewest Include="@(_BuildStaticWebAssetsTargetPath)" Condition="'%(CopyToOutputDirectory)' == 'PreserveNewest'" />
+      <_BuildStaticWebAssetsIfDifferent Include="@(_BuildStaticWebAssetsTargetPath)" Condition="'%(CopyToOutputDirectory)' == 'IfDifferent'" />
     </ItemGroup>
 
   </Target>
@@ -537,8 +538,29 @@ Copyright (c) .NET Foundation. All rights reserved.
     </Copy>
 
   </Target>
+  
+  <Target Name="_BuildCopyStaticWebAssetsIfDifferent"
+    AfterTargets="_SplitStaticWebAssetsByCopyOptions">
+
+    <!--
+        Using SkipUnchangedFiles="true" because we want only differing files.
+    -->
+    <Copy SourceFiles="@(_BuildStaticWebAssetsIfDifferent)"
+      DestinationFiles="@(_BuildStaticWebAssetsIfDifferent->'%(TargetPath)')"
+      SkipUnchangedFiles="true"
+      OverwriteReadOnlyFiles="$(OverwriteReadOnlyFiles)"
+      Retries="$(CopyRetryCount)"
+      RetryDelayMilliseconds="$(CopyRetryDelayMilliseconds)"
+      UseHardlinksIfPossible="$(CreateHardLinksForPublishFilesIfPossible)"
+      UseSymboliclinksIfPossible="$(CreateSymbolicLinksForPublishFilesIfPossible)">
+
+      <Output TaskParameter="DestinationFiles" ItemName="FileWrites"/>
+
+    </Copy>
+
+  </Target>
 
-  <Target Name="WriteStaticWebAssetsUpToDateCheck" DependsOnTargets="_BuildCopyStaticWebAssetsPreserveNewest;_BuildCopyStaticWebAssetsAlways">
+  <Target Name="WriteStaticWebAssetsUpToDateCheck" DependsOnTargets="_BuildCopyStaticWebAssetsPreserveNewest;_BuildCopyStaticWebAssetsAlways;_BuildCopyStaticWebAssetsIfDifferent">
 
     <ItemGroup>
       <_UpToDateCheckStaticWebAssetCandidate Include="@(StaticWebAsset)" Condition="'%(SourceType)' == 'Discovered'" />
diff --git a/src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.Publish.targets b/src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.Publish.targets
index 728f17b43132..487dc196fb04 100644
--- a/src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.Publish.targets
+++ b/src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.Publish.targets
@@ -268,6 +268,7 @@ Copyright (c) .NET Foundation. All rights reserved.
           DependsOnTargets="_IncrementalCleanPublishDirectory;
                             _CopyResolvedFilesToPublishPreserveNewest;
                             _CopyResolvedFilesToPublishAlways;
+                            _CopyResolvedFilesToPublishIfDifferent;
                             _HandleFileConflictsForPublish" />
 
   <!--
@@ -410,6 +411,33 @@ Copyright (c) .NET Foundation. All rights reserved.
 
     </Copy>
   </Target>
+  
+  <!--
+    ============================================================
+                                        _CopyResolvedFilesToPublishIfDifferent
+
+    Copy _ResolvedFileToPublishIfDifferent items to the publish directory
+    ============================================================
+    -->
+  <Target Name="_CopyResolvedFilesToPublishIfDifferent"
+          DependsOnTargets="_ComputeResolvedFilesToPublishTypes">
+
+    <!--
+      Using SkipUnchangedFiles="true" because we want only differing files.
+      -->
+    <Copy SourceFiles = "@(_ResolvedFileToPublishIfDifferent)"
+          DestinationFiles="@(_ResolvedFileToPublishIfDifferent->'$(PublishDir)%(RelativePath)')"
+          SkipUnchangedFiles="true"
+          OverwriteReadOnlyFiles="$(OverwriteReadOnlyFiles)"
+          Retries="$(CopyRetryCount)"
+          RetryDelayMilliseconds="$(CopyRetryDelayMilliseconds)"
+          UseHardlinksIfPossible="$(CreateHardLinksForPublishFilesIfPossible)"
+          UseSymboliclinksIfPossible="$(CreateSymbolicLinksForPublishFilesIfPossible)">
+
+      <Output TaskParameter="DestinationFiles" ItemName="FileWrites"/>
+
+    </Copy>
+  </Target>
 
   <UsingTask TaskName="ResolveReadyToRunCompilers" AssemblyFile="$(MicrosoftNETBuildTasksAssembly)" />
   <Target Name="ResolveReadyToRunCompilers">
@@ -431,7 +459,7 @@ Copyright (c) .NET Foundation. All rights reserved.
     ============================================================
                                         _ComputeResolvedFilesToPublishTypes
 
-    Splits ResolvedFileToPublish items into 'PreserveNewest' and 'Always' buckets.
+    Splits ResolvedFileToPublish items into 'PreserveNewest', 'Always' and 'IfDifferent' buckets.
     Then further splits those into 'Unbundled' buckets based on the single file setting.
     ============================================================
     -->
@@ -443,6 +471,9 @@ Copyright (c) .NET Foundation. All rights reserved.
 
       <_ResolvedFileToPublishAlways Include="@(ResolvedFileToPublish)"
                                     Condition="'%(ResolvedFileToPublish.CopyToPublishDirectory)'=='Always'" />
+                                    
+      <_ResolvedFileToPublishIfDifferent Include="@(ResolvedFileToPublish)"
+                                    Condition="'%(ResolvedFileToPublish.CopyToPublishDirectory)'=='IfDifferent'" />
     </ItemGroup>
 
     <ItemGroup>
@@ -456,6 +487,11 @@ Copyright (c) .NET Foundation. All rights reserved.
               Include="@(_ResolvedFileToPublishAlways)"
               Condition="'$(PublishSingleFile)' != 'true' or
                          '%(_ResolvedFileToPublishAlways.ExcludeFromSingleFile)'=='true'" />
+                         
+      <_ResolvedUnbundledFileToPublishIfDifferent
+              Include="@(_ResolvedFileToPublishIfDifferent)"
+              Condition="'$(PublishSingleFile)' != 'true' or
+                         '%(_ResolvedFileToPublishIfDifferent.ExcludeFromSingleFile)'=='true'" />
     </ItemGroup>
   </Target>
 
@@ -784,6 +820,12 @@ Copyright (c) .NET Foundation. All rights reserved.
         <CopyToPublishDirectory>PreserveNewest</CopyToPublishDirectory>
         <IsKeyOutput Condition="'%(_SourceItemsToCopyToPublishDirectory.FullPath)' == '$(AppHostIntermediatePath)'">True</IsKeyOutput>
       </ResolvedFileToPublish>
+      
+      <ResolvedFileToPublish Include="@(_SourceItemsToCopyToPublishDirectoryIfDifferent)">
+        <RelativePath>%(_SourceItemsToCopyToPublishDirectoryIfDifferent.TargetPath)</RelativePath>
+        <CopyToPublishDirectory>IfDifferent</CopyToPublishDirectory>
+        <IsKeyOutput Condition="'%(_SourceItemsToCopyToPublishDirectoryIfDifferent.FullPath)' == '$(AppHostIntermediatePath)'">True</IsKeyOutput>
+      </ResolvedFileToPublish>
     </ItemGroup>
 
   </Target>
@@ -845,6 +887,10 @@ Copyright (c) .NET Foundation. All rights reserved.
                                             KeepMetadata="$(_GCTPDIKeepMetadata)"
                                             Include="@(_AllChildProjectPublishItemsWithTargetPath->'%(FullPath)')"
                                             Condition="'%(_AllChildProjectPublishItemsWithTargetPath.CopyToPublishDirectory)'=='PreserveNewest'"/>
+      <_SourceItemsToCopyToPublishDirectoryIfDifferent KeepDuplicates=" '$(_GCTPDIKeepDuplicates)' != 'false' "
+                                            KeepMetadata="$(_GCTPDIKeepMetadata)"
+                                            Include="@(_AllChildProjectPublishItemsWithTargetPath->'%(FullPath)')"
+                                            Condition="'%(_AllChildProjectPublishItemsWithTargetPath.CopyToPublishDirectory)'=='IfDifferent'"/>
     </ItemGroup>
 
     <!-- Remove items which we will never again use - they just sit around taking up memory otherwise -->
@@ -860,6 +906,9 @@ Copyright (c) .NET Foundation. All rights reserved.
       <_SourceItemsToCopyToPublishDirectory KeepMetadata="$(_GCTPDIKeepMetadata)"
                                             Include="@(ContentWithTargetPath->'%(FullPath)')"
                                             Condition="'%(ContentWithTargetPath.CopyToPublishDirectory)'=='PreserveNewest'"/>
+      <_SourceItemsToCopyToPublishDirectoryIfDifferent KeepMetadata="$(_GCTPDIKeepMetadata)"
+                                            Include="@(ContentWithTargetPath->'%(FullPath)')"
+                                            Condition="'%(ContentWithTargetPath.CopyToPublishDirectory)'=='IfDifferent'"/>
     </ItemGroup>
 
     <ItemGroup>
@@ -869,11 +918,14 @@ Copyright (c) .NET Foundation. All rights reserved.
       <_SourceItemsToCopyToPublishDirectory KeepMetadata="$(_GCTPDIKeepMetadata)"
                                             Include="@(EmbeddedResource->'%(FullPath)')"
                                             Condition="'%(EmbeddedResource.CopyToPublishDirectory)'=='PreserveNewest'"/>
+      <_SourceItemsToCopyToPublishDirectoryIfDifferent KeepMetadata="$(_GCTPDIKeepMetadata)"
+                                            Include="@(EmbeddedResource->'%(FullPath)')"
+                                            Condition="'%(EmbeddedResource.CopyToPublishDirectory)'=='IfDifferent'"/>
     </ItemGroup>
 
     <ItemGroup>
       <_CompileItemsToPublish Include="@(Compile->'%(FullPath)')"
-                              Condition="'%(Compile.CopyToPublishDirectory)'=='Always' or '%(Compile.CopyToPublishDirectory)'=='PreserveNewest'"/>
+                              Condition="'%(Compile.CopyToPublishDirectory)'=='Always' or '%(Compile.CopyToPublishDirectory)'=='PreserveNewest'" or '%(Compile.CopyToPublishDirectory)'=='IfDifferent'"/>
     </ItemGroup>
 
     <AssignTargetPath Files="@(_CompileItemsToPublish)" RootFolder="$(MSBuildProjectDirectory)">
@@ -887,6 +939,9 @@ Copyright (c) .NET Foundation. All rights reserved.
       <_SourceItemsToCopyToPublishDirectory KeepMetadata="$(_GCTPDIKeepMetadata)"
                                            Include="@(_CompileItemsToPublishWithTargetPath)"
                                            Condition="'%(_CompileItemsToPublishWithTargetPath.CopyToPublishDirectory)'=='PreserveNewest'"/>
+      <_SourceItemsToCopyToPublishDirectoryIfDifferent KeepMetadata="$(_GCTPDIKeepMetadata)"
+                                           Include="@(_CompileItemsToPublishWithTargetPath)"
+                                           Condition="'%(_CompileItemsToPublishWithTargetPath.CopyToPublishDirectory)'=='IfDifferent'"/>
     </ItemGroup>
 
     <ItemGroup>
@@ -896,12 +951,16 @@ Copyright (c) .NET Foundation. All rights reserved.
       <_SourceItemsToCopyToPublishDirectory KeepMetadata="$(_GCTPDIKeepMetadata)"
                                             Include="@(_NoneWithTargetPath->'%(FullPath)')"
                                             Condition="'%(_NoneWithTargetPath.CopyToPublishDirectory)'=='PreserveNewest'"/>
+      <_SourceItemsToCopyToPublishDirectoryIfDifferent KeepMetadata="$(_GCTPDIKeepMetadata)"
+                                            Include="@(_NoneWithTargetPath->'%(FullPath)')"
+                                            Condition="'%(_NoneWithTargetPath.CopyToPublishDirectory)'=='IfDifferent'"/>
     </ItemGroup>
 
     <ItemGroup Condition="'$(_UseSingleFileHostForPublish)' == 'true' and Exists('$(SingleFileHostIntermediatePath)')">
       <!-- Remove non-single-file apphost from items to publish -->
       <_SourceItemsToCopyToPublishDirectoryAlways Remove="$(AppHostIntermediatePath)" />
       <_SourceItemsToCopyToPublishDirectory Remove="$(AppHostIntermediatePath)" />
+      <_SourceItemsToCopyToPublishDirectoryIfDifferent Remove="$(AppHostIntermediatePath)" />
 
       <!-- Add the single-file host created as part of publish -->
       <_SourceItemsToCopyToPublishDirectoryAlways Include="$(SingleFileHostIntermediatePath)" CopyToOutputDirectory="Always" TargetPath="$(AssemblyName)$(_NativeExecutableExtension)" />
@@ -911,13 +970,14 @@ Copyright (c) .NET Foundation. All rights reserved.
       <!-- Remove apphost from build from items to publish -->
       <_SourceItemsToCopyToPublishDirectoryAlways Remove="$(AppHostIntermediatePath)" />
       <_SourceItemsToCopyToPublishDirectory Remove="$(AppHostIntermediatePath)" />
+      <_SourceItemsToCopyToPublishDirectoryIfDifferent Remove="$(AppHostIntermediatePath)" />
 
       <!-- Add the apphost created as part of publish -->
       <_SourceItemsToCopyToPublishDirectoryAlways Include="$(AppHostForPublishIntermediatePath)" CopyToOutputDirectory="Always" TargetPath="$(AssemblyName)$(_NativeExecutableExtension)" />
     </ItemGroup>
 
     <ItemGroup>
-      <AllPublishItemsFullPathWithTargetPath Include="@(_SourceItemsToCopyToPublishDirectoryAlways->'%(FullPath)');@(_SourceItemsToCopyToPublishDirectory->'%(FullPath)')"/>
+      <AllPublishItemsFullPathWithTargetPath Include="@(_SourceItemsToCopyToPublishDirectoryAlways->'%(FullPath)');@(_SourceItemsToCopyToPublishDirectory->'%(FullPath)');@(_SourceItemsToCopyToPublishDirectoryIfDifferent->'%(FullPath)')"/>
     </ItemGroup>
 
   </Target>
@@ -927,7 +987,7 @@ Copyright (c) .NET Foundation. All rights reserved.
                                         DefaultCopyToPublishDirectoryMetadata
 
     If CopyToPublishDirectory isn't set on these items, the value should be taken from CopyToOutputDirectory.
-    This way, projects can just set "CopyToOutputDirectory = Always/PreserveNewest" and by default the item will be copied
+    This way, projects can just set "CopyToOutputDirectory = Always/PreserveNewest/IfDifferent" and by default the item will be copied
     to both the build output and publish directories.
     ============================================================
     -->
@@ -942,6 +1002,9 @@ Copyright (c) .NET Foundation. All rights reserved.
       <ContentWithTargetPath Condition="'%(ContentWithTargetPath.CopyToOutputDirectory)'=='PreserveNewest' and '%(ContentWithTargetPath.CopyToPublishDirectory)' == ''">
         <CopyToPublishDirectory>PreserveNewest</CopyToPublishDirectory>
       </ContentWithTargetPath>
+      <ContentWithTargetPath Condition="'%(ContentWithTargetPath.CopyToOutputDirectory)'=='IfDifferent' and '%(ContentWithTargetPath.CopyToPublishDirectory)' == ''">
+        <CopyToPublishDirectory>IfDifferent</CopyToPublishDirectory>
+      </ContentWithTargetPath>
 
       <EmbeddedResource Condition="'%(EmbeddedResource.CopyToOutputDirectory)'=='Always' and '%(EmbeddedResource.CopyToPublishDirectory)' == ''">
         <CopyToPublishDirectory>Always</CopyToPublishDirectory>
@@ -949,6 +1012,9 @@ Copyright (c) .NET Foundation. All rights reserved.
       <EmbeddedResource Condition="'%(EmbeddedResource.CopyToOutputDirectory)'=='PreserveNewest' and '%(EmbeddedResource.CopyToPublishDirectory)' == ''">
         <CopyToPublishDirectory>PreserveNewest</CopyToPublishDirectory>
       </EmbeddedResource>
+      <EmbeddedResource Condition="'%(EmbeddedResource.CopyToOutputDirectory)'=='IfDifferent' and '%(EmbeddedResource.CopyToPublishDirectory)' == ''">
+        <CopyToPublishDirectory>IfDifferent</CopyToPublishDirectory>
+      </EmbeddedResource>
 
       <Compile Condition="'%(Compile.CopyToOutputDirectory)'=='Always' and '%(Compile.CopyToPublishDirectory)' == ''">
         <CopyToPublishDirectory>Always</CopyToPublishDirectory>
@@ -956,6 +1022,9 @@ Copyright (c) .NET Foundation. All rights reserved.
       <Compile Condition="'%(Compile.CopyToOutputDirectory)'=='PreserveNewest' and '%(Compile.CopyToPublishDirectory)' == ''">
         <CopyToPublishDirectory>PreserveNewest</CopyToPublishDirectory>
       </Compile>
+      <Compile Condition="'%(Compile.CopyToOutputDirectory)'=='IfDifferent' and '%(Compile.CopyToPublishDirectory)' == ''">
+        <CopyToPublishDirectory>IfDifferent</CopyToPublishDirectory>
+      </Compile>
 
       <_NoneWithTargetPath Condition="'%(_NoneWithTargetPath.CopyToOutputDirectory)'=='Always' and '%(_NoneWithTargetPath.CopyToPublishDirectory)' == ''">
         <CopyToPublishDirectory>Always</CopyToPublishDirectory>
@@ -963,6 +1032,9 @@ Copyright (c) .NET Foundation. All rights reserved.
       <_NoneWithTargetPath Condition="'%(_NoneWithTargetPath.CopyToOutputDirectory)'=='PreserveNewest' and '%(_NoneWithTargetPath.CopyToPublishDirectory)' == ''">
         <CopyToPublishDirectory>PreserveNewest</CopyToPublishDirectory>
       </_NoneWithTargetPath>
+      <_NoneWithTargetPath Condition="'%(_NoneWithTargetPath.CopyToOutputDirectory)'=='IfDifferent' and '%(_NoneWithTargetPath.CopyToPublishDirectory)' == ''">
+        <CopyToPublishDirectory>IfDifferent</CopyToPublishDirectory>
+      </_NoneWithTargetPath>
 
     </ItemGroup>
   </Target>