diff --git a/Lib/test/test_httpservers.py b/Lib/test/test_httpservers.py
index d78ae9a6bf1..d9e40634100 100644
--- a/Lib/test/test_httpservers.py
+++ b/Lib/test/test_httpservers.py
@@ -62,6 +62,7 @@ class BaseTestCase(unittest.TestCase):
 
     def tearDown(self):
         self.thread.stop()
+        self.thread = None
         os.environ.__exit__()
         support.threading_cleanup(*self._threads)