diff --git a/test/IISIntegration.FunctionalTests/Properties/AssemblyInfo.cs b/test/IISIntegration.FunctionalTests/Properties/AssemblyInfo.cs
index ebca2988e8..240f2d35c0 100644
--- a/test/IISIntegration.FunctionalTests/Properties/AssemblyInfo.cs
+++ b/test/IISIntegration.FunctionalTests/Properties/AssemblyInfo.cs
@@ -2,4 +2,7 @@
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
 // All functional tests in this project require a version of IIS express with an updated schema
+using Xunit;
+
 [assembly: Microsoft.AspNetCore.Server.IISIntegration.FunctionalTests.IISExpressSupportsInProcessHosting]
+[assembly: CollectionBehavior(DisableTestParallelization = true)]