diff --git a/tox.ini b/tox.ini
index b04a297..43a90fa 100644
--- a/tox.ini
+++ b/tox.ini
@@ -8,7 +8,7 @@ commands =
     coverage report
     coverage xml
     # mypy won't install on PyPy, so only run the typechecking on CPython
-    !pypy3: mypy.stubtest --allowlist dev/mypy.allowlist contextlib2
+    !pypy3: python -m mypy.stubtest --allowlist dev/mypy.allowlist contextlib2
 deps =
     coverage
     !pypy3: mypy