diff --git a/Lib/test/test_threading.py b/Lib/test/test_threading.py
index 0db028864d2..162a72ea03f 100644
--- a/Lib/test/test_threading.py
+++ b/Lib/test/test_threading.py
@@ -1066,6 +1066,8 @@ class ThreadingExceptionTests(BaseTestCase):
         thread.join()
         self.assertIsNotNone(thread.exc)
         self.assertIsInstance(thread.exc, RuntimeError)
+        # explicitly break the reference cycle to not leak a dangling thread
+        thread.exc = None
 
 class TimerTests(BaseTestCase):