diff --git a/tox.ini b/tox.ini
index 0c4de05d..3512bfb6 100644
--- a/tox.ini
+++ b/tox.ini
@@ -19,8 +19,8 @@ envlist = py27, py35, py36, py37, docs
 passenv = *
 usedevelop = True
 deps =
+    py36,py37: black
     isort
-    black
     pylint
     pytest
     pytest-xdist