diff --git a/spec/ruby/default.mspec b/spec/ruby/default.mspec
index 1e8f8893aa..2ebd455fd0 100644
--- a/spec/ruby/default.mspec
+++ b/spec/ruby/default.mspec
@@ -47,5 +47,6 @@ class MSpecScript
     /\wSpecs?$/,
     /^CS_CONST/,
     /^CSL_CONST/,
+    /^RactorLocalSingleton/,
   ]
 end