diff --git a/Lib/test/libregrtest/utils.py b/Lib/test/libregrtest/utils.py
index fb13fa0e243ba7..fd46819fd903fe 100644
--- a/Lib/test/libregrtest/utils.py
+++ b/Lib/test/libregrtest/utils.py
@@ -210,6 +210,13 @@ def clear_caches():
     else:
         fractions._hash_algorithm.cache_clear()
 
+    try:
+        inspect = sys.modules['inspect']
+    except KeyError:
+        pass
+    else:
+        inspect._shadowed_dict_from_mro_tuple.cache_clear()
+
 
 def get_build_info():
     # Get most important configure and build options as a list of strings.