diff --git a/src/libraries/System.Threading/tests/ThreadLocalTests.cs b/src/libraries/System.Threading/tests/ThreadLocalTests.cs
index 236c78f3c4a82b..b6a1e1569c89f2 100644
--- a/src/libraries/System.Threading/tests/ThreadLocalTests.cs
+++ b/src/libraries/System.Threading/tests/ThreadLocalTests.cs
@@ -224,6 +224,7 @@ public static void RunThreadLocalTest7_WeakReference()
         }
 
         [ConditionalFact(typeof(PlatformDetection), nameof(PlatformDetection.IsThreadingSupported))]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/43981", TestRuntimes.Mono)]
         public static void RunThreadLocalTest8_Values()
         {
             // Test adding values and updating values