diff --git a/tox.ini b/tox.ini
index a4a2735..d201af1 100644
--- a/tox.ini
+++ b/tox.ini
@@ -13,7 +13,7 @@ setenv = VIRTUAL_ENV={envdir}
          LC_ALL=en_US.UTF-8
          TESTS_DIR=./virtualbmc/tests/unit/
 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 =