diff --git a/Lib/test/test_imp.py b/Lib/test/test_imp.py
--- a/Lib/test/test_imp.py
+++ b/Lib/test/test_imp.py
@@ -279,7 +279,10 @@
         # see #18681
         from html import parser
         del sys.modules['html']
-        def cleanup(): del sys.modules['html.parser']
+        def cleanup():
+            for mod in list(sys.modules):
+                if mod.startswith('html.'):
+                    del sys.modules[mod]
         self.addCleanup(cleanup)
         with self.assertRaisesRegex(ImportError, 'html'):
             imp.reload(parser)