diff --git a/tox.ini b/tox.ini
index 9e60b20..dd2ab9b 100644
--- a/tox.ini
+++ b/tox.ini
@@ -4,5 +4,6 @@ skipsdist = True
 envlist = py27,py33,py34
 
 [testenv:venv]
+basepython = python3
 commands = {posargs}