diff --git a/docs/requirements.txt b/docs/requirements.txt
new file mode 100644
index 0000000..bbbff4e
--- /dev/null
+++ b/docs/requirements.txt
@@ -0,0 +1,2 @@
+Pillow
+Sphinx
diff --git a/tox.ini b/tox.ini
index c72e118..5b02102 100644
--- a/tox.ini
+++ b/tox.ini
@@ -11,3 +11,7 @@ deps =
 [testenv:style]
 deps = flake8
 commands = flake8 stevedore setup.py
+
+[testenv:docs]
+deps = -r{toxinidir}/docs/requirements.txt
+commands = python setup.py build_sphinx