diff --git a/esphomeyaml/guides/contributing.rst b/esphomeyaml/guides/contributing.rst
index 2cc333173..d8af80baf 100644
--- a/esphomeyaml/guides/contributing.rst
+++ b/esphomeyaml/guides/contributing.rst
@@ -176,7 +176,7 @@ To check your documentation changes locally, you first need install sphinx (**wi
 
 .. code:: bash
 
-    pip3 install sphinx
+    pip3 install sphinx breathe
 
 Then, use the provided Makefile to build the changes and start a simple web server: