diff --git a/tox.ini b/tox.ini
index 23532eb..748607c 100644
--- a/tox.ini
+++ b/tox.ini
@@ -13,7 +13,7 @@ setenv =
    OS_STDERR_CAPTURE=1
    OS_TEST_TIMEOUT=60
 deps =
-  -c{env:UPPER_CONSTRAINTS_FILE:https://opendev.org/openstack/requirements/raw/branch/master/upper-constraints.txtx}
+  -c{env:UPPER_CONSTRAINTS_FILE:https://opendev.org/openstack/requirements/raw/branch/master/upper-constraints.txt}
   -r{toxinidir}/requirements.txt
   -r{toxinidir}/test-requirements.txt
 commands = stestr run {posargs}