diff --git a/.readthedocs.yml b/.readthedocs.yml
index 83cf7bc..e149eb7 100644
--- a/.readthedocs.yml
+++ b/.readthedocs.yml
@@ -7,6 +7,8 @@ build:
   jobs:
     post_checkout:
       - git fetch --shallow-since=2023-01-01  || true
+  apt_packages:
+    - graphviz
 
 submodules:
   include: all