diff --git a/src/libraries/System.Threading.Thread/tests/ThreadTests.cs b/src/libraries/System.Threading.Thread/tests/ThreadTests.cs
index 443c500fd8e804..5bc54ba6b75b60 100644
--- a/src/libraries/System.Threading.Thread/tests/ThreadTests.cs
+++ b/src/libraries/System.Threading.Thread/tests/ThreadTests.cs
@@ -160,6 +160,7 @@ public static IEnumerable<object[]> ApartmentStateTest_MemberData()
 
         [ConditionalTheory(typeof(PlatformDetection), nameof(PlatformDetection.IsNotWindowsNanoServer))]
         [ActiveIssue("https://github.com/dotnet/runtime/issues/34543", TestPlatforms.Windows, TargetFrameworkMonikers.Netcoreapp, TestRuntimes.Mono)]
+        [PlatformSpecific(~TestPlatforms.Browser)] // System.Diagnostics.Process is not supported on this platform.
         [InlineData("STAMain.exe", "GetApartmentStateTest")]
         [InlineData("STAMain.exe", "SetApartmentStateTest")]
         [InlineData("STAMain.exe", "WaitAllNotSupportedOnSta_Test0")]
diff --git a/src/libraries/tests.proj b/src/libraries/tests.proj
index 98273a01002a84..626c4ea4992f8d 100644
--- a/src/libraries/tests.proj
+++ b/src/libraries/tests.proj
@@ -37,7 +37,6 @@
     <ProjectExclusions Include="$(MSBuildThisFileDirectory)System.Net.WebSockets.Client\tests\System.Net.WebSockets.Client.Tests.csproj" />
     <ProjectExclusions Include="$(MSBuildThisFileDirectory)System.ObjectModel\tests\System.ObjectModel.Tests.csproj" />
     <ProjectExclusions Include="$(MSBuildThisFileDirectory)System.Private.Uri\tests\FunctionalTests\System.Private.Uri.Functional.Tests.csproj" />
-    <ProjectExclusions Include="$(MSBuildThisFileDirectory)System.Threading.Thread\tests\System.Threading.Thread.Tests.csproj" />
     <ProjectExclusions Include="$(MSBuildThisFileDirectory)System.ValueTuple\tests\System.ValueTuple.Tests.csproj" />
   </ItemGroup>