diff --git a/etc/ci/buildbot_steps.yml b/etc/ci/buildbot_steps.yml
index 0ffd5279512..a7a8e12a78b 100644
--- a/etc/ci/buildbot_steps.yml
+++ b/etc/ci/buildbot_steps.yml
@@ -77,6 +77,7 @@ linux-rel-css:
   - ./mach test-css --release --processes 16 --log-raw test-css.log --log-errorsummary css-errorsummary.log
   - ./mach build-cef --release
   - ./mach build-geckolib --release
+  - ./mach test-stylo --release
   - bash ./etc/ci/lockfile_changed.sh
   - bash ./etc/ci/manifest_changed.sh