diff --git a/tox.ini b/tox.ini
index 76a2a05f664..c0a6f2c5472 100644
--- a/tox.ini
+++ b/tox.ini
@@ -142,6 +142,7 @@ envdir = {toxworkdir}/docs
 deps =
   -c{env:TOX_CONSTRAINTS_FILE:https://releases.openstack.org/constraints/upper/master}
   -r{toxinidir}/doc/requirements.txt
+  -r{toxinidir}/requirements.txt
 commands = sphinx-build -W -b html doc/source doc/build/html
 
 [testenv:pdf-docs]