diff --git a/tox.ini b/tox.ini
index 3608ea809..9bea18c52 100644
--- a/tox.ini
+++ b/tox.ini
@@ -7,7 +7,7 @@ ignore_basepython_conflict = True
 [testenv]
 basepython = python3
 setenv = VIRTUAL_ENV={envdir}
-deps = -c{env:UPPER_CONSTRAINTS_FILE:https://releases.openstack.org/constraints/upper/master}
+deps = -c{env:TOX_CONSTRAINTS_FILE:https://releases.openstack.org/constraints/upper/master}
 passenv = *_proxy *_PROXY
 
 [testenv:venv]