diff --git a/.readthedocs.yml b/.readthedocs.yml
index bf9cfe15a..7889c2c9d 100644
--- a/.readthedocs.yml
+++ b/.readthedocs.yml
@@ -10,6 +10,8 @@ build:
   tools:
     python: "3"
     rust: "1.55"
+  apt_packages:
+    - graphviz
 
 python:
    install: