diff --git a/doc/requirements.txt b/doc/requirements.txt
new file mode 100644
index 000000000..bdccdcce4
--- /dev/null
+++ b/doc/requirements.txt
@@ -0,0 +1,3 @@
+oslo.config>=5.1.0 # Apache-2.0
+openstackdocstheme>=1.17.0 # Apache-2.0
+sphinx>=1.6.2 # BSD
diff --git a/test-requirements.txt b/test-requirements.txt
index e0bc4f305..87919a814 100644
--- a/test-requirements.txt
+++ b/test-requirements.txt
@@ -36,7 +36,3 @@ reno>=2.5.0 # Apache-2.0
 pysnmp>=4.2.3 # BSD
 osprofiler>=1.4.0 # Apache-2.0
 SQLAlchemy!=1.1.5,!=1.1.6,!=1.1.7,!=1.1.8,>=1.0.10 # MIT
-
-# Doc requirements
-openstackdocstheme>=1.17.0 # Apache-2.0
-sphinx>=1.6.2 # BSD
diff --git a/tox.ini b/tox.ini
index ee536857a..6fad1b9a2 100644
--- a/tox.ini
+++ b/tox.ini
@@ -35,7 +35,11 @@ commands =
     coverage report
 
 [testenv:docs]
-commands = python setup.py build_sphinx
+deps =
+    -c{env:UPPER_CONSTRAINTS_FILE:https://git.openstack.org/cgit/openstack/requirements/plain/upper-constraints.txt}
+        -r{toxinidir}/requirements.txt
+        -r{toxinidir}/doc/requirements.txt
+commands = sphinx-build -W -b html doc/source doc/build/html
 
 [testenv:debug]
 commands = oslo_debug_helper {posargs}