diff --git a/.github/workflows/ci.yaml b/.github/workflows/ci.yaml
index ea9505454..ebc31b82e 100644
--- a/.github/workflows/ci.yaml
+++ b/.github/workflows/ci.yaml
@@ -21,6 +21,7 @@ jobs:
           python -m pip install -e .[dev]
           python -m pip install -e .[test]
           python -m pip install ltd-conveyor
+          python -m pip install sphinxext-rediraffe
       - name: Build documentation
         run: |
           cd doc