diff --git a/src/libraries/System.Private.Uri/tests/FunctionalTests/IriTest.cs b/src/libraries/System.Private.Uri/tests/FunctionalTests/IriTest.cs
index d018c93750739d..c2dcd58228498c 100644
--- a/src/libraries/System.Private.Uri/tests/FunctionalTests/IriTest.cs
+++ b/src/libraries/System.Private.Uri/tests/FunctionalTests/IriTest.cs
@@ -238,7 +238,7 @@ public void Iri_UnicodePlane2()
             EscapeUnescapeTestUnicodePlane(0x20000, 0x2FFFF);
         }
 
-        [Fact]
+        [ConditionalFact(typeof(PlatformDetection), nameof(PlatformDetection.Is64BitProcess))]
         public void Iri_UnicodePlane3_13()
         {
             EscapeUnescapeTestUnicodePlane(0x30000, 0xDFFFF);