diff --git a/tox.ini b/tox.ini
index 37b7d874..a854dd53 100644
--- a/tox.ini
+++ b/tox.ini
@@ -11,7 +11,7 @@ setenv =
    VIRTUAL_ENV={envdir}
    PYTHONWARNINGS=default::DeprecationWarning
 deps =
-    -c{env:UPPER_CONSTRAINTS_FILE:https://releases.openstack.org/constraints/upper/master}
+    -c{env:TOX_CONSTRAINTS_FILE:https://releases.openstack.org/constraints/upper/master}
     -r{toxinidir}/test-requirements.txt
     -r{toxinidir}/requirements.txt
 commands = stestr run {posargs}