diff --git a/tox.ini b/tox.ini
index a776cd5..511b3d3 100644
--- a/tox.ini
+++ b/tox.ini
@@ -8,7 +8,7 @@ ignore_basepython_conflict = True
 basepython = python3
 usedevelop = True
 whitelist_externals = rm
-install_command = pip install -c{env:UPPER_CONSTRAINTS_FILE:https://git.openstack.org/cgit/openstack/requirements/plain/upper-constraints.txt} {opts} {packages}
+install_command = pip install -c{env:TOX_CONSTRAINTS_FILE:https://git.openstack.org/cgit/openstack/requirements/plain/upper-constraints.txt} {opts} {packages}
 setenv =
    VIRTUAL_ENV={envdir}
    PYTHONWARNINGS=default::DeprecationWarning