diff --git a/Lib/test/regrtest.py b/Lib/test/regrtest.py
index a323965..df8a7b0 100755
--- a/Lib/test/regrtest.py
+++ b/Lib/test/regrtest.py
@@ -370,6 +370,10 @@
             print()   # Force a newline (just in case)
             print(json.dumps(result))
             sys.exit(0)
+        else:
+            print(("No handler for option {}.  Please report this as a bug "
+                  "at http://bugs.python.org.").format(o), file=sys.stderr)
+            sys.exit(1)
     if single and fromfile:
         usage("-s and -f don't go together!")
     if use_mp and trace: