diff --git a/src/libraries/System.Net.Http/tests/FunctionalTests/HttpClientHandlerTest.Http3.cs b/src/libraries/System.Net.Http/tests/FunctionalTests/HttpClientHandlerTest.Http3.cs
index b3551199a2994..fe784a9c8d0c9 100644
--- a/src/libraries/System.Net.Http/tests/FunctionalTests/HttpClientHandlerTest.Http3.cs
+++ b/src/libraries/System.Net.Http/tests/FunctionalTests/HttpClientHandlerTest.Http3.cs
@@ -27,6 +27,7 @@ public HttpClientHandlerTest_Http3(ITestOutputHelper output) : base(output)
         }
 
         [Theory]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/55774")]
         [InlineData(10)] // 2 bytes settings value.
         [InlineData(100)] // 4 bytes settings value.
         [InlineData(10_000_000)] // 8 bytes settings value.