diff --git a/dist/tools/backport_pr/backport_pr.py b/dist/tools/backport_pr/backport_pr.py
index f2f46c13e4..fba9ed0a2d 100755
--- a/dist/tools/backport_pr/backport_pr.py
+++ b/dist/tools/backport_pr/backport_pr.py
@@ -224,7 +224,7 @@ def main():
             sys.exit(5)
     print(f"Backport based on branch {release_fullname}")
 
-    repo = git.Repo(args.gitdir)
+    repo = git.Repo(args.gitdir, search_parent_directories=True)
     # Fetch current upstream
     upstream_remote = _get_upstream(repo)
     if not upstream_remote: