@@ -485,6 +485,19 @@ class MyList(list):
         self.assertFalse(type_issubtype(frozendict, dict))
         self.assertFalse(type_issubtype(MyList, tuple))
 
+    def test_subclass_type_with_dict_subclass_tp_dict(self):
+        # gh-132042: MyListDictSubclass initializes tp_dict with a dict
+        # subclass before PyType_Ready(), as extensions may do.  Creating a
+        # subclass must still find the special methods in that dict.
+        class Sub(_testcapi.MyListDictSubclass):
+            pass
+        self.assertEqual(len(Sub([1, 2, 3])), 3)
+
+        class Sub2(_testcapi.MyListDictSubclass):
+            def __len__(self):
+                return 5
+        self.assertEqual(len(Sub2([1, 2, 3])), 5)
+
     def test_type_modified(self):
         # Test PyType_Modified()
         type_modified = _testlimitedcapi.type_modified
 
@@ -3281,6 +3281,17 @@ static PyTypeObject MyList_Type = {
     MyList_new,                                 /* tp_new */
 };
 
+/* Like MyList, but tp_dict is initialized with a dict subclass before
+   PyType_Ready(), as extension modules may do (e.g. ctypes before 3.13). */
+static PyTypeObject MyListDictSubclass_Type = {
+    PyVarObject_HEAD_INIT(NULL, 0)
+    "MyListDictSubclass",
+    sizeof(MyListObject),
+    .tp_dealloc = MyList_dealloc,
+    .tp_flags = Py_TPFLAGS_DEFAULT | Py_TPFLAGS_BASETYPE,
+    .tp_new = MyList_new,
+};
+
 /* Test PEP 560 */
 
 typedef struct {
@@ -3597,6 +3608,28 @@ _testcapi_exec(PyObject *m)
     Py_INCREF(&MyList_Type);
     PyModule_AddObject(m, "MyList", (PyObject *)&MyList_Type);
 
+    MyListDictSubclass_Type.tp_base = &PyList_Type;
+    if (MyListDictSubclass_Type.tp_dict == NULL) {
+        PyObject *cls = PyObject_CallFunction((PyObject *)&PyType_Type,
+                                              "s(O){}", "DictSubclass",
+                                              &PyDict_Type);
+        if (cls == NULL) {
+            return -1;
+        }
+        MyListDictSubclass_Type.tp_dict = PyObject_CallNoArgs(cls);
+        Py_DECREF(cls);
+        if (MyListDictSubclass_Type.tp_dict == NULL) {
+            return -1;
+        }
+    }
+    /* PyModule_AddType() would skip PyType_Ready() as tp_dict is set. */
+    if (PyType_Ready(&MyListDictSubclass_Type) < 0) {
+        return -1;
+    }
+    if (PyModule_AddType(m, &MyListDictSubclass_Type) < 0) {
+        return -1;
+    }
+
     if (PyType_Ready(&GenericAlias_Type) < 0)
         return -1;
     Py_INCREF(&GenericAlias_Type);