diff --git a/Lib/pdb.py b/Lib/pdb.py
index f695a39332e461..f5d01e1e362343 100644
--- a/Lib/pdb.py
+++ b/Lib/pdb.py
@@ -3577,6 +3577,11 @@ def main():
             parser.error("argument -m: not allowed with argument --pid")
         try:
             attach(opts.pid, opts.commands)
+        except RuntimeError as e:
+            while e.__context__ is not None:
+                e = e.__context__
+            print(f"Error attaching to process: {e}")
+            sys.exit(1)
         except PermissionError as e:
             exit_with_permission_help_text()
         return
diff --git a/Misc/NEWS.d/next/Library/2025-10-11-09-07-06.gh-issue-139940.g54efZ.rst b/Misc/NEWS.d/next/Library/2025-10-11-09-07-06.gh-issue-139940.g54efZ.rst
new file mode 100644
index 00000000000000..55b691a42693d9
--- /dev/null
+++ b/Misc/NEWS.d/next/Library/2025-10-11-09-07-06.gh-issue-139940.g54efZ.rst
@@ -0,0 +1 @@
+Print clearer error message when using pdb to attaching to a non-existing process on Linux.