diff --git a/tox.ini b/tox.ini
index 6b1da79..22385cb 100644
--- a/tox.ini
+++ b/tox.ini
@@ -13,7 +13,7 @@ setenv = VIRTUAL_ENV={envdir}
          NOSE_OPENSTACK_YELLOW=0.025
          NOSE_OPENSTACK_SHOW_ELAPSED=1
 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}/requirements.txt
   -r{toxinidir}/test-requirements.txt
 commands =