diff --git a/tox.ini b/tox.ini
index ed28636d3a..5bb2268c4f 100644
--- a/tox.ini
+++ b/tox.ini
@@ -34,7 +34,9 @@ commands = bash -c "find {toxinidir}             \
          -print0 | xargs -0 bashate -v -iE006 -eE005,E042"
 
 [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
 whitelist_externals = bash
 setenv =
   TOP_DIR={toxinidir}