diff --git a/test_requirements.txt b/test_requirements.txt
index e70e856..fbb72b6 100644
--- a/test_requirements.txt
+++ b/test_requirements.txt
@@ -4,5 +4,5 @@ flake8
 ipdb
 mixer
 mock
-tox
+tox==4.18.1
 django-compat