diff --git a/Lib/test/test_types.py b/Lib/test/test_types.py
index da32c4ea6477ced..e92fd397d845f8a 100644
--- a/Lib/test/test_types.py
+++ b/Lib/test/test_types.py
@@ -640,6 +640,11 @@ def test_traceback_and_frame_types(self):
     def test_capsule_type(self):
         self.assertIsInstance(_datetime.datetime_CAPI, types.CapsuleType)
 
+    def test_timezone_base_type(self):
+        class MyTimezone(_datetime.timezone):
+            pass
+
+        self.assertIs(issubclass(MyTimezone, _datetime.timezone), True)
 
 class UnionTests(unittest.TestCase):
 
diff --git a/Misc/NEWS.d/next/Library/2023-11-29-12-55-55.gh-issue-112451.KFFlYs.rst b/Misc/NEWS.d/next/Library/2023-11-29-12-55-55.gh-issue-112451.KFFlYs.rst
new file mode 100644
index 000000000000000..c55d4f66fe415c1
--- /dev/null
+++ b/Misc/NEWS.d/next/Library/2023-11-29-12-55-55.gh-issue-112451.KFFlYs.rst
@@ -0,0 +1 @@
+Make C-extension ``datetime.timezone`` acceptable as a base class.
diff --git a/Modules/_datetimemodule.c b/Modules/_datetimemodule.c
index cb5403e8461ff0e..38802f806d3537f 100644
--- a/Modules/_datetimemodule.c
+++ b/Modules/_datetimemodule.c
@@ -4107,7 +4107,7 @@ static PyTypeObject PyDateTime_TimeZoneType = {
     0,                                /* tp_getattro */
     0,                                /* tp_setattro */
     0,                                /* tp_as_buffer */
-    Py_TPFLAGS_DEFAULT,               /* tp_flags */
+    Py_TPFLAGS_DEFAULT | Py_TPFLAGS_BASETYPE, /* tp_flags */
     timezone_doc,                     /* tp_doc */
     0,                                /* tp_traverse */
     0,                                /* tp_clear */