diff --git a/.github/workflows/pr-auto-close.yml b/.github/workflows/pr-auto-close.yml
new file mode 100644
index 0000000000..9471088053
--- /dev/null
+++ b/.github/workflows/pr-auto-close.yml
@@ -0,0 +1,18 @@
+name: Auto-Close Pull Requests Sagitta
+
+on:
+  pull_request_target:
+    types:
+      - opened
+    branches:
+      - sagitta
+
+jobs:
+  run:
+    runs-on: ubuntu-latest
+    steps:
+    - uses: superbrothers/close-pull-request@v3
+      with:
+        # Optional. Post a issue comment just before closing a pull request.
+        comment: "Pull requests to this branch are not accepted and have been closed automatically."
+        github_token: ${{ secrets.PAT }}