diff --git a/tox.ini b/tox.ini
index 7906f6d..11a0ee8 100644
--- a/tox.ini
+++ b/tox.ini
@@ -14,7 +14,7 @@ envlist =
 downloadcache = {toxworkdir}/_download/
 commands =
     django-admin.py --version
-    {envpython} runtests.py
+    {envpython} runtests.py {posargs}
 basepython =
     py27: python2.7
     py34: python3.4