diff --git a/tox.ini b/tox.ini
index ff4d7999..c334443f 100644
--- a/tox.ini
+++ b/tox.ini
@@ -16,6 +16,7 @@ deps =
     greenlet
     blinker
     python-dotenv
+    argparse
 
     lowest: Werkzeug==0.9
     lowest: Jinja2==2.4