diff --git a/tox.ini b/tox.ini
index 3db3a8ef..fbe285e2 100644
--- a/tox.ini
+++ b/tox.ini
@@ -20,7 +20,7 @@ passenv = *
 usedevelop = True
 deps =
     py36,py37,py38: black
-    isort
+    isort<5
     pylint
     pytest
     pytest-xdist