diff --git a/src/System.Security.Permissions/ref/System.Security.Permissions.Forwards.cs b/src/System.Security.Permissions/ref/System.Security.Permissions.Forwards.cs
index 6b9b7f457fe1..6183ea30a71b 100644
--- a/src/System.Security.Permissions/ref/System.Security.Permissions.Forwards.cs
+++ b/src/System.Security.Permissions/ref/System.Security.Permissions.Forwards.cs
@@ -18,3 +18,4 @@
 [assembly: System.Runtime.CompilerServices.TypeForwardedTo(typeof(System.Security.PermissionSet))]
 [assembly: System.Runtime.CompilerServices.TypeForwardedTo(typeof(System.Security.Permissions.PermissionState))]
 #endif
+
diff --git a/src/System.Security.Permissions/ref/System.Security.Permissions.cs b/src/System.Security.Permissions/ref/System.Security.Permissions.cs
index f38b82cfeb01..e862fa284023 100644
--- a/src/System.Security.Permissions/ref/System.Security.Permissions.cs
+++ b/src/System.Security.Permissions/ref/System.Security.Permissions.cs
@@ -2091,33 +2091,4 @@ public enum AspNetHostingPermissionLevel
         Unrestricted = 600,
     }
 }
-namespace System.Xaml.Permissions
-{
-    public partial class XamlAccessLevel
-    {
-        internal XamlAccessLevel() { }
-        public System.Reflection.AssemblyName AssemblyAccessToAssemblyName { get { throw null; } }
-        public string PrivateAccessToTypeName { get { throw null; } }
-        public static System.Xaml.Permissions.XamlAccessLevel AssemblyAccessTo(System.Reflection.Assembly assembly) { throw null; }
-        public static System.Xaml.Permissions.XamlAccessLevel AssemblyAccessTo(System.Reflection.AssemblyName assemblyName) { throw null; }
-        public static System.Xaml.Permissions.XamlAccessLevel PrivateAccessTo(string assemblyQualifiedTypeName) { throw null; }
-        public static System.Xaml.Permissions.XamlAccessLevel PrivateAccessTo(System.Type type) { throw null; }
-    }
-    public sealed partial class XamlLoadPermission : System.Security.CodeAccessPermission, System.Security.Permissions.IUnrestrictedPermission
-    {
-        public XamlLoadPermission(System.Collections.Generic.IEnumerable<System.Xaml.Permissions.XamlAccessLevel> allowedAccess) { }
-        public XamlLoadPermission(System.Security.Permissions.PermissionState state) { }
-        public XamlLoadPermission(System.Xaml.Permissions.XamlAccessLevel allowedAccess) { }
-        public System.Collections.Generic.IList<System.Xaml.Permissions.XamlAccessLevel> AllowedAccess { get { throw null; } }
-        public override System.Security.IPermission Copy() { throw null; }
-        public override bool Equals(object obj) { throw null; }
-        public override void FromXml(System.Security.SecurityElement elem) { }
-        public override int GetHashCode() { throw null; }
-        public bool Includes(System.Xaml.Permissions.XamlAccessLevel requestedAccess) { throw null; }
-        public override System.Security.IPermission Intersect(System.Security.IPermission target) { throw null; }
-        public override bool IsSubsetOf(System.Security.IPermission target) { throw null; }
-        public bool IsUnrestricted() { throw null; }
-        public override System.Security.SecurityElement ToXml() { throw null; }
-        public override System.Security.IPermission Union(System.Security.IPermission other) { throw null; }
-    }
-}
+
diff --git a/src/System.Security.Permissions/ref/System.Security.Permissions.csproj b/src/System.Security.Permissions/ref/System.Security.Permissions.csproj
index d2b4c998d46c..4372861e3128 100644
--- a/src/System.Security.Permissions/ref/System.Security.Permissions.csproj
+++ b/src/System.Security.Permissions/ref/System.Security.Permissions.csproj
@@ -1,4 +1,4 @@
-<Project Sdk="Microsoft.NET.Sdk">
+<Project Sdk="Microsoft.NET.Sdk">
   <PropertyGroup>
     <ProjectGuid>{07CAF142-B259-418E-86EF-C4BD8B50253E}</ProjectGuid>
     <IsPartialFacadeAssembly Condition="'$(TargetsNetFx)' == 'true'">true</IsPartialFacadeAssembly>
@@ -9,6 +9,9 @@
     <Compile Include="System.Security.Permissions.Forwards.cs" />
     <SuppressPackageTargetFrameworkCompatibility Include="$(UAPvNextTFM)" />
   </ItemGroup>
+  <ItemGroup Condition="'$(TargetGroup)' == 'netcoreapp'">
+    <Compile Include="System.Security.Permissions.netcoreapp.cs" />
+  </ItemGroup>
   <ItemGroup Condition="'$(TargetsNetFx)' == 'true'">
     <Reference Include="mscorlib" />
     <Reference Include="System" />
@@ -39,4 +42,7 @@
     <ProjectReference Include="..\..\System.Text.RegularExpressions\ref\System.Text.RegularExpressions.csproj" />
     <ProjectReference Include="..\..\System.Threading\ref\System.Threading.csproj" />
   </ItemGroup>
+  <ItemGroup Condition="'$(TargetGroup)' == 'netcoreapp'">
+    <ProjectReference Include="..\..\System.Windows.Extensions\ref\System.Windows.Extensions.csproj" />
+  </ItemGroup>
 </Project>
diff --git a/src/System.Security.Permissions/ref/System.Security.Permissions.netcoreapp.cs b/src/System.Security.Permissions/ref/System.Security.Permissions.netcoreapp.cs
new file mode 100644
index 000000000000..5d3c1d7eea6d
--- /dev/null
+++ b/src/System.Security.Permissions/ref/System.Security.Permissions.netcoreapp.cs
@@ -0,0 +1,27 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+// ------------------------------------------------------------------------------
+// Changes to this file must follow the http://aka.ms/api-review process.
+// ------------------------------------------------------------------------------
+
+namespace System.Xaml.Permissions
+{
+    public sealed partial class XamlLoadPermission : System.Security.CodeAccessPermission, System.Security.Permissions.IUnrestrictedPermission
+    {
+        public XamlLoadPermission(System.Collections.Generic.IEnumerable<System.Xaml.Permissions.XamlAccessLevel> allowedAccess) { }
+        public XamlLoadPermission(System.Security.Permissions.PermissionState state) { }
+        public XamlLoadPermission(System.Xaml.Permissions.XamlAccessLevel allowedAccess) { }
+        public System.Collections.Generic.IList<System.Xaml.Permissions.XamlAccessLevel> AllowedAccess { get { throw null; } }
+        public override System.Security.IPermission Copy() { throw null; }
+        public override bool Equals(object obj) { throw null; }
+        public override void FromXml(System.Security.SecurityElement elem) { }
+        public override int GetHashCode() { throw null; }
+        public bool Includes(System.Xaml.Permissions.XamlAccessLevel requestedAccess) { throw null; }
+        public override System.Security.IPermission Intersect(System.Security.IPermission target) { throw null; }
+        public override bool IsSubsetOf(System.Security.IPermission target) { throw null; }
+        public bool IsUnrestricted() { throw null; }
+        public override System.Security.SecurityElement ToXml() { throw null; }
+        public override System.Security.IPermission Union(System.Security.IPermission other) { throw null; }
+    }
+}
diff --git a/src/System.Security.Permissions/src/System.Security.Permissions.csproj b/src/System.Security.Permissions/src/System.Security.Permissions.csproj
index 9d3ca6e39fb0..7498d5970e94 100644
--- a/src/System.Security.Permissions/src/System.Security.Permissions.csproj
+++ b/src/System.Security.Permissions/src/System.Security.Permissions.csproj
@@ -1,4 +1,4 @@
-<Project Sdk="Microsoft.NET.Sdk">
+<Project Sdk="Microsoft.NET.Sdk">
   <PropertyGroup>
     <ProjectGuid>{07390899-C8F6-4E83-A3A9-6867B8CB46A0}</ProjectGuid>
     <RootNamespace>System.Security.Permissions</RootNamespace>
@@ -178,7 +178,8 @@
     <Compile Include="System\Web\AspNetHostingPermission.cs" />
     <Compile Include="System\Web\AspNetHostingPermissionAttribute.cs" />
     <Compile Include="System\Web\AspNetHostingPermissionLevel.cs" />
-    <Compile Include="System\Xaml\Permissions\XamlAccessLevel.cs" />
+  </ItemGroup>
+  <ItemGroup Condition="'$(TargetGroup)' == 'netcoreapp'">
     <Compile Include="System\Xaml\Permissions\XamlLoadPermission.cs" />
   </ItemGroup>
   <ItemGroup Condition="'$(TargetGroup)' == 'netstandard'">
@@ -228,4 +229,7 @@
     <Reference Include="System.Threading" />
     <Reference Include="System.Threading.Thread" />
   </ItemGroup>
+  <ItemGroup Condition="'$(TargetGroup)' == 'netcoreapp'">
+    <Reference Include="System.Windows.Extensions" />
+  </ItemGroup>
 </Project>
diff --git a/src/System.Security.Permissions/tests/PermissionTests.cs b/src/System.Security.Permissions/tests/PermissionTests.cs
index e1cf80ff586d..8494d5c2328d 100644
--- a/src/System.Security.Permissions/tests/PermissionTests.cs
+++ b/src/System.Security.Permissions/tests/PermissionTests.cs
@@ -7,7 +7,6 @@
 using System.DirectoryServices;
 using System.Reflection;
 using System.Web;
-using System.Xaml.Permissions;
 
 namespace System.Security.Permissions.Tests
 {
@@ -444,26 +443,6 @@ public static void WebBrowserPermissionAttributeCallMethods()
             IPermission ip = wpa.CreatePermission();
         }
 
-        [Fact]
-        public static void XamlLoadPermissionCallMethods()
-        {
-            XamlAccessLevel accessLevel = XamlAccessLevel.AssemblyAccessTo(Assembly.GetExecutingAssembly().GetName());
-            XamlLoadPermission xp = new XamlLoadPermission(accessLevel);
-            XamlLoadPermission xp2 = new XamlLoadPermission(PermissionState.Unrestricted);
-            XamlLoadPermission xp3 = new XamlLoadPermission(Array.Empty<XamlAccessLevel>());
-            bool testbool = xp.IsUnrestricted();
-            IPermission ip = xp.Copy();
-            IPermission ip2 = xp.Intersect(ip);
-            IPermission ip3 = xp.Union(ip);
-            testbool = xp.IsSubsetOf(ip);
-            testbool = xp.Equals(new object());
-            testbool = xp.Includes(accessLevel);
-            int hash = xp.GetHashCode();
-            SecurityElement se = new SecurityElement("");
-            xp.FromXml(se);
-            se = xp.ToXml();
-        }
-
         [Fact]
         public static void ZoneIdentityPermissionCallMethods()
         {
diff --git a/src/System.Security.Permissions/tests/System.Security.Permissions.Tests.csproj b/src/System.Security.Permissions/tests/System.Security.Permissions.Tests.csproj
index 402e93a13761..bf3edac06971 100644
--- a/src/System.Security.Permissions/tests/System.Security.Permissions.Tests.csproj
+++ b/src/System.Security.Permissions/tests/System.Security.Permissions.Tests.csproj
@@ -18,6 +18,8 @@
     <Compile Include="PrincipalPermissionTests.cs" />
     <Compile Include="SecurityElementTests.cs" />
     <Compile Include="TrustManagerContextTests.cs" />
-    <Compile Include="XamlAccessLevelTests.cs" />
+  </ItemGroup>
+  <ItemGroup Condition="'$(TargetGroup)' == 'netcoreapp' And '$(TargetsWindows)' == 'true'">
+    <Compile Include="XamlLoadPermissionTests.cs"/>
   </ItemGroup>
 </Project>
diff --git a/src/System.Security.Permissions/tests/XamlLoadPermissionTests.cs b/src/System.Security.Permissions/tests/XamlLoadPermissionTests.cs
new file mode 100644
index 000000000000..cb2e5c83548f
--- /dev/null
+++ b/src/System.Security.Permissions/tests/XamlLoadPermissionTests.cs
@@ -0,0 +1,38 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+using Xunit;
+using System.Configuration;
+using System.DirectoryServices;
+using System.Reflection;
+using System.Security;
+using System.Security.Permissions;
+using System.Web;
+using System.Xaml.Permissions;
+
+namespace System.Xaml.Permissions.Tests
+{
+    public class XamlLoadPermissionTests
+    {
+        [Fact]
+        public static void XamlLoadPermissionCallMethods()
+        {
+            XamlAccessLevel accessLevel = XamlAccessLevel.AssemblyAccessTo(Assembly.GetExecutingAssembly().GetName());
+            XamlLoadPermission xp = new XamlLoadPermission(accessLevel);
+            XamlLoadPermission xp2 = new XamlLoadPermission(PermissionState.Unrestricted);
+            XamlLoadPermission xp3 = new XamlLoadPermission(Array.Empty<XamlAccessLevel>());
+            bool testbool = xp.IsUnrestricted();
+            IPermission ip = xp.Copy();
+            IPermission ip2 = xp.Intersect(ip);
+            IPermission ip3 = xp.Union(ip);
+            testbool = xp.IsSubsetOf(ip);
+            testbool = xp.Equals(new object());
+            testbool = xp.Includes(accessLevel);
+            int hash = xp.GetHashCode();
+            SecurityElement se = new SecurityElement("");
+            xp.FromXml(se);
+            se = xp.ToXml();
+        }
+    }
+}
diff --git a/src/System.Windows.Extensions/ref/System.Windows.Extensions.cs b/src/System.Windows.Extensions/ref/System.Windows.Extensions.cs
index 581a77931128..41ebd7db878e 100644
--- a/src/System.Windows.Extensions/ref/System.Windows.Extensions.cs
+++ b/src/System.Windows.Extensions/ref/System.Windows.Extensions.cs
@@ -133,3 +133,16 @@ public enum X509SelectionFlag
         MultiSelection = 1,
     }
 }
+namespace System.Xaml.Permissions
+{
+    public partial class XamlAccessLevel
+    {
+        internal XamlAccessLevel() { }
+        public System.Reflection.AssemblyName AssemblyAccessToAssemblyName { get { throw null; } }
+        public string PrivateAccessToTypeName { get { throw null; } }
+        public static System.Xaml.Permissions.XamlAccessLevel AssemblyAccessTo(System.Reflection.Assembly assembly) { throw null; }
+        public static System.Xaml.Permissions.XamlAccessLevel AssemblyAccessTo(System.Reflection.AssemblyName assemblyName) { throw null; }
+        public static System.Xaml.Permissions.XamlAccessLevel PrivateAccessTo(string assemblyQualifiedTypeName) { throw null; }
+        public static System.Xaml.Permissions.XamlAccessLevel PrivateAccessTo(System.Type type) { throw null; }
+    }
+}
diff --git a/src/System.Windows.Extensions/src/System.Windows.Extensions.csproj b/src/System.Windows.Extensions/src/System.Windows.Extensions.csproj
index fc4a9bf2f39e..c45d8a141716 100644
--- a/src/System.Windows.Extensions/src/System.Windows.Extensions.csproj
+++ b/src/System.Windows.Extensions/src/System.Windows.Extensions.csproj
@@ -71,6 +71,7 @@
     <Compile Include="System\Media\SoundPlayer.cs" />
     <Compile Include="System\Media\SystemSound.cs" />
     <Compile Include="System\Media\SystemSounds.cs" />
+    <Compile Include="System\Xaml\Permissions\XamlAccessLevel.cs" />
   </ItemGroup>
   <ItemGroup Condition="'$(TargetGroup)' == 'netcoreapp'">
     <Reference Include="System.Buffers" />
diff --git a/src/System.Security.Permissions/src/System/Xaml/Permissions/XamlAccessLevel.cs b/src/System.Windows.Extensions/src/System/Xaml/Permissions/XamlAccessLevel.cs
similarity index 96%
rename from src/System.Security.Permissions/src/System/Xaml/Permissions/XamlAccessLevel.cs
rename to src/System.Windows.Extensions/src/System/Xaml/Permissions/XamlAccessLevel.cs
index 7bea5cf0a9bc..80b5fef5f7f4 100644
--- a/src/System.Security.Permissions/src/System/Xaml/Permissions/XamlAccessLevel.cs
+++ b/src/System.Windows.Extensions/src/System/Xaml/Permissions/XamlAccessLevel.cs
@@ -1,4 +1,4 @@
-// Licensed to the .NET Foundation under one or more agreements.
+// Licensed to the .NET Foundation under one or more agreements.
 // The .NET Foundation licenses this file to you under the MIT license.
 // See the LICENSE file in the project root for more information.
 
diff --git a/src/System.Windows.Extensions/tests/System.Windows.Extensions.Tests.csproj b/src/System.Windows.Extensions/tests/System.Windows.Extensions.Tests.csproj
index b0836e434797..a7eeb64c180a 100644
--- a/src/System.Windows.Extensions/tests/System.Windows.Extensions.Tests.csproj
+++ b/src/System.Windows.Extensions/tests/System.Windows.Extensions.Tests.csproj
@@ -6,6 +6,7 @@
   <ItemGroup Condition="'$(TargetsWindows)' == 'true'">
     <Compile Include="X509Certificate2UITests.cs" />
     <Compile Include="X509Certificate2UIManualTests.cs" />
+    <Compile Include="XamlAccessLevelTests.cs" />
   </ItemGroup>
   <ItemGroup>
     <Compile Include="$(CommonTestPath)\System\Drawing\Helpers.cs">
diff --git a/src/System.Security.Permissions/tests/XamlAccessLevelTests.cs b/src/System.Windows.Extensions/tests/XamlAccessLevelTests.cs
similarity index 93%
rename from src/System.Security.Permissions/tests/XamlAccessLevelTests.cs
rename to src/System.Windows.Extensions/tests/XamlAccessLevelTests.cs
index a1488ee20835..d321b85ec87d 100644
--- a/src/System.Security.Permissions/tests/XamlAccessLevelTests.cs
+++ b/src/System.Windows.Extensions/tests/XamlAccessLevelTests.cs
@@ -1,4 +1,4 @@
-// Licensed to the .NET Foundation under one or more agreements.
+// Licensed to the .NET Foundation under one or more agreements.
 // The .NET Foundation licenses this file to you under the MIT license.
 // See the LICENSE file in the project root for more information.