diff --git a/doc/requirements.txt b/doc/requirements.txt
new file mode 100644
index 0000000..500cb6c
--- /dev/null
+++ b/doc/requirements.txt
@@ -0,0 +1,3 @@
+sphinx!=1.6.6,>=1.6.2,<2.0.0;python_version=='2.7' # BSD
+sphinx!=1.6.6,>=1.6.2;python_version>='3.4' # BSD
+sphinx_rtd_theme
diff --git a/test-requirements.txt b/test-requirements.txt
index a349a26..18d2ecb 100644
--- a/test-requirements.txt
+++ b/test-requirements.txt
@@ -4,8 +4,3 @@ fixtures>=0.3.14
 python-subunit>=0.0.18
 stestr
 testtools>=0.9.36,!=1.2.0
-
-# docs
-sphinx!=1.6.6,>=1.6.2,<2.0.0;python_version=='2.7' # BSD
-sphinx!=1.6.6,>=1.6.2;python_version>='3.4' # BSD
-sphinx_rtd_theme
diff --git a/tox.ini b/tox.ini
index 02a863a..f9fb916 100644
--- a/tox.ini
+++ b/tox.ini
@@ -22,6 +22,8 @@ basepython = python3
 commands = {posargs}
 
 [testenv:docs]
+deps = -c{env:TOX_CONSTRAINTS_FILE:https://releases.openstack.org/constraints/upper/master}
+       -r{toxinidir}/doc/requirements.txt
 commands = sphinx-build -W -b html doc/source doc/build/html
 
 [testenv:pep8]