diff --git a/tox.ini b/tox.ini
index 921fee1..b99d209 100644
--- a/tox.ini
+++ b/tox.ini
@@ -7,7 +7,7 @@
 [testenv]
 basepython = python3
 usedevelop = True
-install_command = pip install -c{env:UPPER_CONSTRAINTS_FILE:https://releases.openstack.org/constraints/upper/master} {opts} {packages}
+install_command = pip install -c{env:TOX_CONSTRAINTS_FILE:https://releases.openstack.org/constraints/upper/master} {opts} {packages}
 setenv =
    VIRTUAL_ENV={envdir}
    PYTHONWARNINGS=default::DeprecationWarning