diff --git a/tox.ini b/tox.ini
index b1ab30b..72bf206 100644
--- a/tox.ini
+++ b/tox.ini
@@ -1,11 +1,7 @@
 [tox]
 envlist =
-    py27-django14,
-    py27-django13,
-    py27-django12,
-    py26-django14,
-    py26-django13,
-    py26-django12
+    py27-django14, py27-django13, py27-django12,
+    py26-django14, py26-django13, py26-django12
 
 [testenv]
 changedir = tests
@@ -13,31 +9,37 @@ setenv = PYTHONPATH = {toxinidir}/tests
 commands = django-admin.py test core --settings=settings
 
 [testenv:py27-django14]
+basepython = python2.7
 deps =
     Django>=1.4
     Pillow
 
 [testenv:py27-django13]
+basepython = python2.7
 deps =
     Django>=1.3,<=1.4
     Pillow
 
 [testenv:py27-django12]
+basepython = python2.7
 deps =
     Django>=1.2,<=1.3
     Pillow
 
 [testenv:py26-django14]
+basepython = python2.6
 deps =
     Django>=1.4
     Pillow
 
 [testenv:py26-django13]
+basepython = python2.6
 deps =
     Django>=1.3,<=1.4
     Pillow
 
 [testenv:py26-django12]
+basepython = python2.6
 deps =
     Django>=1.2,<=1.3
     Pillow