diff --git a/docs/source/requirements.txt b/docs/source/requirements.txt
new file mode 100644
index 0000000..77bd874
--- /dev/null
+++ b/docs/source/requirements.txt
@@ -0,0 +1,4 @@
+sphinx>=1.3.0
+sphinx_rtd_theme
+sphinx-prompt
+configparser
diff --git a/tox.ini b/tox.ini
index 1be408f..03d30c8 100644
--- a/tox.ini
+++ b/tox.ini
@@ -88,9 +88,7 @@ commands =
 [testenv:docs]
 basepython = python3
 deps =
-    sphinx>=1.3.0
-    sphinx_rtd_theme
-    sphinx-prompt
+    -rdocs/source/requirements.txt
 commands =
     sphinx-build -E -W -c docs/source/ -b html docs/source/ docs/build/html