diff --git a/.gitea/workflows/deploy-pages.yml b/.gitea/workflows/deploy-pages.yml
index 520a5acca..02bf60e1a 100644
--- a/.gitea/workflows/deploy-pages.yml
+++ b/.gitea/workflows/deploy-pages.yml
@@ -23,7 +23,7 @@ jobs:
       - name: Install system dependencies
         run: |
           apt-get update
-          apt-get install -y doxygen
+          apt-get install -y doxygen graphviz
 
       - name: Build musrfit-tech-docu
         run: |