diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index 62325ced30bd44603aa1e3f9a48698a80f77f102..a1dea3ece17c56b236df0f0437fcdf5c9ee49957 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -47,6 +47,7 @@ stages:
       - source /storage/app/miniconda3/bin/activate /storage/app/EWS_prod/envs/conda/py3EWS/
       - pip install coverage
       - pip install sphinx
+      - pip install sphinx-build
       - python3 -V  # Print out python version for debugging
       - mkdir $PACKAGES_DIR
       - mkdir -p $OUTPUT_DIR