diff --git a/tox.ini b/tox.ini
index 99969b6925..70b5d53437 100644
--- a/tox.ini
+++ b/tox.ini
@@ -14,7 +14,9 @@ passenv = *_proxy *_PROXY
 commands = {posargs}
 
 [testenv:docs]
-deps = -r{toxinidir}/doc/requirements.txt
+deps =
+  -c{env:TOX_CONSTRAINTS_FILE:https://releases.openstack.org/constraints/upper/master}
+  -r{toxinidir}/doc/requirements.txt
 commands =
   rm -rf doc/build
   docstheme-build-translated.sh