diff --git a/tox.ini b/tox.ini
index c3a1f519..61d6a098 100644
--- a/tox.ini
+++ b/tox.ini
@@ -32,6 +32,7 @@ commands=
 
 [testenv:py34]
 extras=
+    flask
 
 [testenv:pypy]
 commands=