diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index de121ab12bbe32365fe4fc2e61b36e8f1bd21927..508d7a931f77481766773978c1c569578b7efc33 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -79,7 +79,7 @@ unit-test-job:   # This job runs in the test stage.
 pages:
   stage: deploy
   script:
-  - pip install -U sphinx m2r2 furo graphviz pyUML
+  - pip install -U sphinx m2r2 furo graphviz pyUML pydot
   - pip install -e .
   - mkdir public
   - cd public