diff --git a/.readthedocs.yml b/.readthedocs.yml
index c42963f09..a91352d41 100644
--- a/.readthedocs.yml
+++ b/.readthedocs.yml
@@ -14,3 +14,5 @@ build:
   os: ubuntu-22.04
   tools:
     python: "3.11"
+  apt_packages:
+    - graphviz