diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index d4bde7d..e22a813 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -49,6 +49,8 @@ compile darwin:
   extends: .multitarget-darwin
   stage: native library
   tags: [darwin-builder]
+  before_script:
+    - brew install cmake
   script:
     - git clone https://github.com/signalapp/libsignal-client
     - cd libsignal-client && git checkout "$libsignal_version"