diff --git a/Directory.Build.props b/Directory.Build.props
index 3229abc41..93d370757 100644
--- a/Directory.Build.props
+++ b/Directory.Build.props
@@ -11,6 +11,17 @@
     <ToolSetCommonDirectory>$(MSBuildThisFileDirectory)artifacts\toolset\Common\</ToolSetCommonDirectory>
   </PropertyGroup>
 
+  <!-- Need to set ProjectAssetsFile to something so it doesn't get set to the Tools.proj assets file when we import the generated props -->
+  <PropertyGroup>
+    <ProjectAssetsFile Condition="'$(ProjectAssetsFile)' == ''">unused</ProjectAssetsFile>
+  </PropertyGroup>
+
+  <Import Project="$(ToolSetCommonDirectory)Tools.proj.nuget.g.props" Condition="Exists('$(ToolSetCommonDirectory)Tools.proj.nuget.g.props')" />
+
+  <PropertyGroup>
+    <ProjectAssetsFile Condition="'$(ProjectAssetsFile)' == 'unused'"></ProjectAssetsFile>
+  </PropertyGroup>
+
   <!-- Common repo directories -->
   <PropertyGroup>
     <ProjectDir>$(MSBuildThisFileDirectory)</ProjectDir>
@@ -31,13 +42,9 @@
     <EnableDefaultCompileItems>false</EnableDefaultCompileItems>
   </PropertyGroup>
 
-  <!-- Need to set ProjectAssetsFile to something so it doesn't get set to the Tools.proj assets file when we import the generated props -->
-  <PropertyGroup>
-    <ProjectAssetsFile Condition="'$(ProjectAssetsFile)' == ''">unused</ProjectAssetsFile>
-  </PropertyGroup>
-  <Import Project="$(ToolSetCommonDirectory)Tools.proj.nuget.g.props" Condition="Exists('$(ToolSetCommonDirectory)Tools.proj.nuget.g.props')" />
+  <!-- Set maximum version for NetStandard to 2.1, since we're now producing 2.1 out of this repo -->
   <PropertyGroup>
-    <ProjectAssetsFile Condition="'$(ProjectAssetsFile)' == 'unused'"></ProjectAssetsFile>
+    <NETStandardMaximumVersion>2.1</NETStandardMaximumVersion>
   </PropertyGroup>
 
   <!-- workaround https://github.com/dotnet/sdk/issues/2288
diff --git a/NuGet.config b/NuGet.config
index d1cfbfaf7..c7c5414c0 100644
--- a/NuGet.config
+++ b/NuGet.config
@@ -1,5 +1,10 @@
 <?xml version="1.0" encoding="utf-8"?>
 <configuration>
+  <!-- Don't use any higher level config files.
+       Our builds need to be isolated from user/machine state -->
+  <fallbackPackageFolders>
+    <clear />
+  </fallbackPackageFolders>
   <packageSources>
     <clear />
     <add key="dotnet-core" value="https://dotnetfeed.blob.core.windows.net/dotnet-core/index.json" />
diff --git a/eng/Tools.props b/eng/Tools.props
index de84b9810..da22c5059 100644
--- a/eng/Tools.props
+++ b/eng/Tools.props
@@ -11,6 +11,8 @@
 
     <!-- Need to keep in sync with CodeAnalysis.targets file. -->
     <AnalyzerPropsFile>$(ArtifactsToolsetDir)Common\Tools.Analyzers.props</AnalyzerPropsFile>
+    <!-- Don't use implicit fallback folder for packages -->
+    <DisableImplicitNuGetFallbackFolder>true</DisableImplicitNuGetFallbackFolder>
   </PropertyGroup>
   <ItemGroup>
     <PackageReference Include="Microsoft.DotNet.ApiCompat" Version="$(MicrosoftDotNetApiCompatPackageVersion)" />
@@ -22,6 +24,8 @@
     <PackageReference Include="Microsoft.SourceLink.GitHub" Version="$(MicrosoftSourceLinkVersion)" PrivateAssets="all" IsImplicitlyDefined="true" />
     <PackageReference Include="Microsoft.SourceLink.Vsts.Git" Version="$(MicrosoftSourceLinkVersion)" PrivateAssets="all" IsImplicitlyDefined="true" />
 
+    <PackageReference Include="$(NetStandardLibraryPackage)" Version="$(NetStandardLibraryPackageVersion)" ExcludeAssets="All" />
+
     <!-- Reference analyzers -->
     <PackageReference Include="Desktop.Analyzers" Version="1.1.0" />
     <PackageReference Include="Microsoft.DotNet.CodeAnalysis" Version="$(MicrosoftDotNetCodeAnalysisPackageVersion)" />
diff --git a/eng/Version.Details.xml b/eng/Version.Details.xml
index 5a4036b64..d2a0cfc7d 100644
--- a/eng/Version.Details.xml
+++ b/eng/Version.Details.xml
@@ -22,5 +22,8 @@
       <Uri>https://github.com/dotnet/arcade</Uri>
       <Sha>52d4b539dd1ab771015bdf33ed4221afcaaabf3d</Sha>
     </Dependency>
+    <PinnedDependency Name="NETStandard.Library" Version="2.0.3">
+      <Uri>https://github.com/dotnet/standard</Uri>
+    </PinnedDependency>
   </ToolsetDependencies>
 </Dependencies>
diff --git a/eng/Versions.props b/eng/Versions.props
index 5d1b1a37d..bade01467 100644
--- a/eng/Versions.props
+++ b/eng/Versions.props
@@ -20,10 +20,18 @@
     <XmlDocPackage>Microsoft.Private.Intellisense</XmlDocPackage>
     <XmlDocPackageVersion>2.0.0-preview3-26209-0</XmlDocPackageVersion>
   </PropertyGroup>
+
+  <PropertyGroup>
+    <NetStandardLibraryPackage>netstandard.library</NetStandardLibraryPackage>
+  </PropertyGroup>
+
   <PropertyGroup>
     <MicrosoftDotNetApiCompatPackageVersion>1.0.0-beta.19061.6</MicrosoftDotNetApiCompatPackageVersion>
     <MicrosoftDotNetBuildTasksPackagingPackageVersion>1.0.0-beta.19061.6</MicrosoftDotNetBuildTasksPackagingPackageVersion>
     <MicrosoftDotNetCodeAnalysisPackageVersion>1.0.0-beta.19061.6</MicrosoftDotNetCodeAnalysisPackageVersion>
     <MicrosoftDotNetGenAPIPackageVersion>1.0.0-beta.19061.6</MicrosoftDotNetGenAPIPackageVersion>
+
+    <!-- This is the LKG stable version of NetStandard.Library from myget.org. Please don't edit this version -->
+    <NetStandardLibraryPackageVersion>2.0.3</NetStandardLibraryPackageVersion>
   </PropertyGroup>
 </Project>
diff --git a/src/netstandard/pkg/NETStandard.Library.pkgproj b/src/netstandard/pkg/NETStandard.Library.pkgproj
index 458513896..95ddd9942 100644
--- a/src/netstandard/pkg/NETStandard.Library.pkgproj
+++ b/src/netstandard/pkg/NETStandard.Library.pkgproj
@@ -10,7 +10,7 @@
     <SkipValidatePackage>true</SkipValidatePackage>
     <TargetsFileName>NETStandard.Library.targets</TargetsFileName>
     <VersionTargetsTemplate>targets\netstandard\$(TargetsFileName)</VersionTargetsTemplate>
-    <NETStandardVersion>netstandard2.0</NETStandardVersion>
+    <NETStandardVersion>netstandard2.1</NETStandardVersion>
     <VersionTargetsSource>$(IntermediateOutputPath)$(NETStandardVersion)\$(TargetsFileName)</VersionTargetsSource>
   </PropertyGroup>
 
@@ -25,6 +25,10 @@
       <Facade>true</Facade>
     </ProjectReference>
 
+    <NetStandard20Files Include="$(PackagesDir)$(NetStandardLibraryPackage)/$(NetStandardLibraryPackageVersion)/build/netstandard2.0/**">
+      <TargetPath>build/netstandard2.0/%(RecursiveDir)%(Filename)%(Extension)</TargetPath>
+    </NetStandard20Files>
+
     <File Include="$(VersionTargetsSource)">
       <TargetPath>build/$(NETStandardVersion)/$(Id).targets</TargetPath>
     </File>
@@ -32,8 +36,14 @@
     <File Include="$(PlaceHolderFile)">
       <TargetPath>lib/netstandard1.0</TargetPath>
     </File>
+
+    <File Include="@(NetStandard20Files)" />
   </ItemGroup>
 
+  <Target Name="EnsureRestoredNetStandardAssets" BeforeTargets="GenerateNuSpec">
+    <Error Condition="'@(NetStandard20Files)' == ''" Text="Could not find package assets for netstandard2.0" />
+  </Target>
+
   <Target Name="StampTargets" BeforeTargets="GenerateNuSpec">
     <PropertyGroup>
       <_FacadeFiles Condition="'%(File.Facade)' == 'true' AND '%(File.Extension)' == '.dll'" >@(File->'%24(MSBuildThisFileDirectory)ref\%(FileName)%(Extension)')</_FacadeFiles>
diff --git a/src/netstandard/pkg/shims/netfx/Directory.Build.props b/src/netstandard/pkg/shims/netfx/Directory.Build.props
index c90b9e656..b0da79628 100644
--- a/src/netstandard/pkg/shims/netfx/Directory.Build.props
+++ b/src/netstandard/pkg/shims/netfx/Directory.Build.props
@@ -2,7 +2,7 @@
 <Project ToolsVersion="12.0" DefaultTargets="Build" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
   <PropertyGroup>
     <ShimRelOutputPath>netfx</ShimRelOutputPath>
-    <TargetFramework>netstandard2.0</TargetFramework>
+    <TargetFramework>netstandard2.1</TargetFramework>
     <!-- Treat this as a reference assembly because it needs to packaged in the ref folder -->
     <IsReferenceAssembly>true</IsReferenceAssembly>
   </PropertyGroup>
diff --git a/src/netstandard/pkg/shims/netstandard/Directory.Build.props b/src/netstandard/pkg/shims/netstandard/Directory.Build.props
index d48e24cc7..82979bf7e 100644
--- a/src/netstandard/pkg/shims/netstandard/Directory.Build.props
+++ b/src/netstandard/pkg/shims/netstandard/Directory.Build.props
@@ -2,7 +2,7 @@
 <Project ToolsVersion="12.0" DefaultTargets="Build" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
   <PropertyGroup>
     <ShimRelOutputPath>netstandard</ShimRelOutputPath>
-    <TargetFramework>netstandard2.0</TargetFramework>
+    <TargetFramework>netstandard2.1</TargetFramework>
     <!-- Treat this as a reference assembly because it needs to packaged in the ref folder -->
     <IsReferenceAssembly>true</IsReferenceAssembly>
   </PropertyGroup>
diff --git a/src/netstandard/ref/netstandard.csproj b/src/netstandard/ref/netstandard.csproj
index cdf47894d..55fe68fb8 100644
--- a/src/netstandard/ref/netstandard.csproj
+++ b/src/netstandard/ref/netstandard.csproj
@@ -1,8 +1,8 @@
 <Project Sdk="Microsoft.NET.Sdk">
   <PropertyGroup>
-    <AssemblyVersion>2.0.0.0</AssemblyVersion>
+    <AssemblyVersion>2.1.0.0</AssemblyVersion>
     <AllowUnsafeBlocks>true</AllowUnsafeBlocks>
-    <TargetFramework>netstandard2.0</TargetFramework>
+    <TargetFramework>netstandard2.1</TargetFramework>
     <IsCoreAssembly>true</IsCoreAssembly>
     <!-- disable obsolete warnings/errors -->
     <NoWarn>$(NoWarn);0618;0619;0809</NoWarn>
diff --git a/src/netstandard/src/netstandard.csproj b/src/netstandard/src/netstandard.csproj
index a4ab54f3a..25b04d771 100644
--- a/src/netstandard/src/netstandard.csproj
+++ b/src/netstandard/src/netstandard.csproj
@@ -1,11 +1,13 @@
 <Project Sdk="Microsoft.NET.Sdk">
   <PropertyGroup>
     <AssemblyName>netstandard</AssemblyName>
-    <AssemblyVersion>2.0.0.0</AssemblyVersion>
+    <AssemblyVersion>2.1.0.0</AssemblyVersion>
     <TargetFrameworks>net461;xamarin.ios;xamarin.watchos;xamarin.tvos;xamarin.mac;monoandroid</TargetFrameworks>
     <!-- custom target framework settings to satisfy SDK and msbuild. -->
     <TargetFrameworkIdentifier Condition="'$(TargetFramework)' != 'net461'">$(TargetFramework)</TargetFrameworkIdentifier>
     <TargetFrameworkVersion Condition="'$(TargetFramework)' != 'net461'">0.0</TargetFrameworkVersion>
+    <!-- Use fallback until we have a compatibility mapping for netstandard2.1. -->
+    <AssetTargetFallback>netstandard2.1</AssetTargetFallback>
     <DisableImplicitFrameworkReferences>true</DisableImplicitFrameworkReferences>
     <DisableStandardFrameworkResolution>true</DisableStandardFrameworkResolution>
     <ContractProject>..\ref\netstandard.csproj</ContractProject>
diff --git a/src/platforms/Directory.Build.props b/src/platforms/Directory.Build.props
index 05f4356dc..abeedd045 100644
--- a/src/platforms/Directory.Build.props
+++ b/src/platforms/Directory.Build.props
@@ -8,10 +8,10 @@
     <LangVersion>7.2</LangVersion>
 
     <!-- custom target framework settings to satisfy SDK and msbuild. -->
-    <TargetFrameworkVersion Condition="'$(TargetFramework)' != 'net461'">0.0</TargetFrameworkVersion>
-    <TargetFrameworkIdentifier Condition="'$(TargetFramework)' != 'net461'">$(TargetFramework)</TargetFrameworkIdentifier>
+    <TargetFrameworkVersion Condition="!$(TargetFramework.StartsWith('net4')) and !$(TargetFramework.StartsWith('netstandard'))">0.0</TargetFrameworkVersion>
+    <TargetFrameworkIdentifier Condition="!$(TargetFramework.StartsWith('net4')) and !$(TargetFramework.StartsWith('netstandard'))">$(TargetFramework)</TargetFrameworkIdentifier>
     <DisableStandardFrameworkResolution>true</DisableStandardFrameworkResolution>
     <ImplicitlyExpandNETStandardFacades>false</ImplicitlyExpandNETStandardFacades>
     <DisableImplicitFrameworkReferences>true</DisableImplicitFrameworkReferences>
   </PropertyGroup>
-</Project>
\ No newline at end of file
+</Project>
diff --git a/src/platforms/extensions/Directory.Build.props b/src/platforms/extensions/Directory.Build.props
index 9952e36f7..d2f6d898e 100644
--- a/src/platforms/extensions/Directory.Build.props
+++ b/src/platforms/extensions/Directory.Build.props
@@ -1,8 +1,16 @@
 <?xml version="1.0" encoding="utf-8"?>
 <Project DefaultTargets="Build">
   <PropertyGroup>
-    <TargetFramework>net461</TargetFramework>
+    <TargetFramework>netstandard2.1</TargetFramework>
   </PropertyGroup>
+
+  <!-- Disable code paths that require project.assets.json files to be present or to be computed. -->
+  <PropertyGroup>
+    <GenerateDependencyFile>false</GenerateDependencyFile>
+    <ComputeNETCoreBuildOutputFiles>false</ComputeNETCoreBuildOutputFiles>
+    <GenerateRuntimeConfigurationFiles>false</GenerateRuntimeConfigurationFiles>
+  </PropertyGroup>
+  
   <Import Condition="Exists('..\Directory.Build.props')" Project="..\Directory.Build.props" />
 
   <Target Name="MarkProjectReferencesAsNotPrivate" BeforeTargets="AssignProjectConfiguration">