diff --git a/tox.ini b/tox.ini
index 2045733..def878c 100644
--- a/tox.ini
+++ b/tox.ini
@@ -26,7 +26,7 @@ setenv =
   # pip: Avoid 2020-01-01 warnings: https://github.com/pypa/pip/issues/6207
   # paramiko CryptographyDeprecationWarning: https://github.com/ansible/ansible/issues/52598
   PYTHONWARNINGS=ignore:DEPRECATION::pip._internal.cli.base_command,ignore::UserWarning
-  PIP_+  VIRTUAL_ENV={envdir}
+  VIRTUAL_ENV={envdir}
   LANG=en_US.UTF-8
   LANGUAGE=en_US:en
   LC_ALL=C