diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index 5c41172..4eb8358 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -2,6 +2,7 @@ image: python:3.7.3-slim-stretch
 
 pages:
   script:
+  - apt update && apt install build-essential
   - pip3 install -r dev_requirements.txt
   - cd docs
   - make html