diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index 8643562df98aa178be5cc0be8f086c6d5013f4c6..b686f9fe342a4305e963da75f4efb9a48e3b7929 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -27,6 +27,7 @@ ubuntu:
       - $ENABLE_NIGHTLY_BUILDS
   image: i10git.cs.fau.de:5005/pycodegen/pycodegen/minimal_ubuntu
   script:
+    - apt install -y ninja-build
     - python3 -m pip install -e .
     - python3 setup.py test
   tags:
@@ -45,6 +46,7 @@ conda:
       - $ENABLE_NIGHTLY_BUILDS
   image: i10git.cs.fau.de:5005/pycodegen/pycodegen/minimal_conda
   script:
+    - apt install -y ninja-build
     - conda install pip
     - pip install -e .
     - python setup.py test