diff --git a/Lib/test/test_sys.py b/Lib/test/test_sys.py
index edb9c10d7ac..5c2f347bad3 100644
--- a/Lib/test/test_sys.py
+++ b/Lib/test/test_sys.py
@@ -539,6 +539,7 @@ def test_sys_getwindowsversion_no_instantiation(self):
         test.support.get_attribute(sys, "getwindowsversion")
         self.assert_raise_on_new_sys_type(sys.getwindowsversion())
 
+    @test.test_support.cpython_only
     def test_clear_type_cache(self):
         sys._clear_type_cache()