diff --git a/doc/requirements.txt b/doc/requirements.txt
new file mode 100644
index 00000000..7af6a330
--- /dev/null
+++ b/doc/requirements.txt
@@ -0,0 +1,5 @@
+# Documentation
+reno>=3.1.0 # Apache-2.0
+sphinx>=2.0.0,!=2.1.0 # BSD
+openstackdocstheme>=2.2.1 # Apache-2.0
+os-api-ref>=1.4.0 # Apache-2.0
diff --git a/test-requirements.txt b/test-requirements.txt
index 192084f1..08c90830 100644
--- a/test-requirements.txt
+++ b/test-requirements.txt
@@ -10,9 +10,3 @@ testscenarios>=0.4 # Apache-2.0/BSD
 testtools>=2.2.0 # MIT
 coverage!=4.4,>=4.0 # Apache-2.0
 oslotest>=3.2.0 # Apache-2.0
-
-# Documentation
-reno>=3.1.0 # Apache-2.0
-sphinx>=2.0.0,!=2.1.0 # BSD
-openstackdocstheme>=2.2.1 # Apache-2.0
-os-api-ref>=1.4.0 # Apache-2.0
diff --git a/tox.ini b/tox.ini
index e5bedafe..d80784d7 100644
--- a/tox.ini
+++ b/tox.ini
@@ -39,7 +39,8 @@ commands = flake8 {posargs}
 commands = {posargs}
 
 [testenv:docs]
-deps = {[testenv]deps}
+deps = -c{env:TOX_CONSTRAINTS_FILE:https://releases.openstack.org/constraints/upper/master}
+       -r{toxinidir}/doc/requirements.txt
 commands =
     rm -rf doc/html doc/build
     rm -rf doc/source/apidoc doc/source/api
@@ -88,6 +89,7 @@ commands = sphinx-build -a -E -W -d releasenotes/build/doctrees --keep-going -b
 [testenv:api-ref]
 # This environment is called from CI scripts to test and publish
 # the API Ref to docs.openstack.org.
+deps = {[testenv:docs]deps}
 commands =
     rm -rf api-ref/build
     sphinx-build -WE --keep-going -b html -d api-ref/build/doctrees api-ref/source api-ref/build/html