diff --git a/tox.ini b/tox.ini
index 07232014dc..b70f48a982 100644
--- a/tox.ini
+++ b/tox.ini
@@ -9,7 +9,7 @@ basepython = python3
 setenv = VIRTUAL_ENV={envdir}
          PYTHONWARNINGS=default::DeprecationWarning
          OS_TEST_PATH=heat/tests
-install_command = pip install -c{env:UPPER_CONSTRAINTS_FILE:https://releases.openstack.org/constraints/upper/xena} {opts} {packages}
+install_command = pip install -c{env:TOX_CONSTRAINTS_FILE:https://releases.openstack.org/constraints/upper/xena} {opts} {packages}
 usedevelop = True
 deps = -c{env:TOX_CONSTRAINTS_FILE:https://releases.openstack.org/constraints/upper/xena}
        -r{toxinidir}/requirements.txt