diff --git a/README.rst b/README.rst
index a2e45bc..a4f3233 100644
--- a/README.rst
+++ b/README.rst
@@ -76,7 +76,7 @@ for device hotplug enumeration: [optional]
 	libudev-dev
 
 for documentation: [optional]
-	python3-sphinx doxygen
+	python3-sphinx doxygen graphviz
 
 for gstreamer: [optional]
 	libgstreamer1.0-dev libgstreamer-plugins-base1.0-dev