diff --git a/src/libraries/System.Net.Sockets/tests/FunctionalTests/SelectTest.cs b/src/libraries/System.Net.Sockets/tests/FunctionalTests/SelectTest.cs
index 347df8870f1e94..f85a9b0db3dedd 100644
--- a/src/libraries/System.Net.Sockets/tests/FunctionalTests/SelectTest.cs
+++ b/src/libraries/System.Net.Sockets/tests/FunctionalTests/SelectTest.cs
@@ -275,7 +275,11 @@ private static void DisposeSockets(IEnumerable<KeyValuePair<Socket, Socket>> soc
                 Assert.True(pair.Value.SafeHandle.IsClosed);
             }
         }
+    }
 
+    [Collection(nameof(NoParallelTests))]
+    public class SelectTest_NonParallel
+    {
         [OuterLoop]
         [Fact]
         public static async Task Select_AcceptNonBlocking_Success()