diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index a9c4116..7507317 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -4,7 +4,7 @@ image: alpine
 
 pages:
   script:
-  - apk update && apk add doxygen
+  - apk update && apk add doxygen graphviz
   - doxygen Doxyfile
   - mv docs/html/ public/
   artifacts: