diff --git a/tox.ini b/tox.ini
index 56a432002..fef36b790 100644
--- a/tox.ini
+++ b/tox.ini
@@ -32,6 +32,7 @@ commands = oslo_debug_helper -t keystoneclient/tests {posargs}
 
 [testenv:functional]
 setenv = OS_TEST_PATH=./keystoneclient/tests/functional
+passenv = OS_*
 
 [flake8]
 # H405: multi line docstring summary not separated with an empty line