diff --git a/tox.ini b/tox.ini
index b17ab9c05..bc7e97630 100644
--- a/tox.ini
+++ b/tox.ini
@@ -47,7 +47,7 @@ skipsdist = True
 skip_install = True
 sitepackages = False
 setenv =
-  UPPER_CONSTRAINTS_FILE=file:///dev/null
+  TOX_CONSTRAINTS_FILE=file:///dev/null
 deps =
     pre-commit>=2.7.1
     virtualenv>=20.0.31