diff --git a/tox.ini b/tox.ini
index 8d38373..1f5be88 100644
--- a/tox.ini
+++ b/tox.ini
@@ -1,5 +1,5 @@
 [tox]
-envlist = py27,pypy,py34,py35,py36,flake8
+envlist = py27,pypy,py34,py35,py36,pypy3,flake8
 skipsdist = True
 
 [testenv]