diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index 668b25e254e81f80b997a3c3c405a9357b23fd7e..c600dba92ff78650cb350e9bfc7d4eabfb192a33 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -135,7 +135,7 @@ PyPy POCL:
   - tags
 Documentation:
   script:
-  - EXTRA_INSTALL="numpy"
+  - EXTRA_INSTALL="numpy mako"
   - curl -L -O -k https://gitlab.tiker.net/inducer/ci-support/raw/master/build-docs.sh
   - ". ./build-docs.sh"
   tags: