diff --git a/.github/workflows/pull_request.yml b/.github/workflows/pull_request.yml
index c5525d1b..54a76b42 100644
--- a/.github/workflows/pull_request.yml
+++ b/.github/workflows/pull_request.yml
@@ -42,6 +42,14 @@ jobs:
           github-token: ${{ secrets.GITHUB_TOKEN }}
           flag-name: run-${{ matrix.test_number }}
           parallel: true
+      - name: Notify Slack of pipeline completion
+        uses: 8398a7/action-slack@v3
+        if: ${{ github.event.pull_request.head.repo.full_name == github.event.pull_request.base.repo.full_name }}
+        with:
+          status: ${{ job.status }}
+          text: PR built on Ruby {{ matrix.ruby-version }}
+        env:
+          SLACK_WEBHOOK_URL: ${{ secrets.SLACK_WEBHOOK }}
 
   finish:
     needs: test