diff --git a/tox.ini b/tox.ini
index 0e5d5ff..7afe832 100644
--- a/tox.ini
+++ b/tox.ini
@@ -1,5 +1,5 @@
 [tox]
-envlist = py27, py33, py34, py35, py36, py37
+envlist = py27, py33, py34, py35, py36, py37, pypy
 [testenv]
 extras = testing
 deps =