diff --git a/Doc/whatsnew/3.15.rst b/Doc/whatsnew/3.15.rst
index 53628b2ff46..4eece1d8d78 100644
--- a/Doc/whatsnew/3.15.rst
+++ b/Doc/whatsnew/3.15.rst
@@ -789,6 +789,14 @@ base64
   (Contributed by Gregory P. Smith in :gh:`146311`.)
 
 
+bdb
+---
+* :exc:`bdb.BdbQuit` is now a subclass of :exc:`BaseException`, instead of
+  :exc:`Exception`, to allow it to be used for cleanly exiting the debugger without
+  being accidentally caught by user code.
+  (Contributed by Tian Gao in :gh:`149337`.)
+
+
 binascii
 --------
 
diff --git a/Lib/bdb.py b/Lib/bdb.py
index 50cf2b3f5b3..9d4243d8ff7 100644
--- a/Lib/bdb.py
+++ b/Lib/bdb.py
@@ -13,7 +13,7 @@
 GENERATOR_AND_COROUTINE_FLAGS = CO_GENERATOR | CO_COROUTINE | CO_ASYNC_GENERATOR
 
 
-class BdbQuit(Exception):
+class BdbQuit(BaseException):
     """Exception to give up completely."""
 
 
diff --git a/Lib/test/test_bdb.py b/Lib/test/test_bdb.py
index f15dae13eb3..53fda185eb7 100644
--- a/Lib/test/test_bdb.py
+++ b/Lib/test/test_bdb.py
@@ -1237,6 +1237,15 @@ def test_format_stack_entry_no_lineno(self):
         self.assertIn('Warning: lineno is None',
                       Bdb().format_stack_entry((sys._getframe(), None)))
 
+    def test_bdb_quit_base_exception(self):
+        # gh-149309
+        try:
+            raise _bdb.BdbQuit()
+        except Exception:
+            self.fail(f'BdbQuit should not be caught by Exception')
+        except BaseException:
+            pass
+
 
 if __name__ == "__main__":
     unittest.main()
diff --git a/Misc/NEWS.d/next/Library/2026-05-03-22-52-07.gh-issue-149309.gXhk9Y.rst b/Misc/NEWS.d/next/Library/2026-05-03-22-52-07.gh-issue-149309.gXhk9Y.rst
new file mode 100644
index 00000000000..69df9f1f6da
--- /dev/null
+++ b/Misc/NEWS.d/next/Library/2026-05-03-22-52-07.gh-issue-149309.gXhk9Y.rst
@@ -0,0 +1 @@
+:exc:`bdb.BdbQuit` is now a subclass of :exc:`BaseException`, instead of :exc:`Exception`, to allow it to be used for cleanly exiting the debugger without being accidentally caught by user code.