diff --git a/Lib/test/test_descr.py b/Lib/test/test_descr.py
--- a/Lib/test/test_descr.py
+++ b/Lib/test/test_descr.py
@@ -4235,6 +4235,22 @@
         with self.assertRaises(AttributeError):
             del X.__abstractmethods__
 
+    def test_methoddescr_raises_TypeError(self):
+        class FakeStr:
+            # This makes isinstance(FakeStr(), str) true
+            __class__ = str
+
+        with self.assertRaises(TypeError):
+            str.split(FakeStr())
+
+    def test_wrapperdescr_raises_TypeError(self):
+        class FakeStr:
+            # This makes isinstance(FakeStr(), str) true
+            __class__ = str
+
+        with self.assertRaises(TypeError):
+            str.__add__(FakeStr(), "")
+
 
 class DictProxyTests(unittest.TestCase):
     def setUp(self):
diff --git a/Objects/descrobject.c b/Objects/descrobject.c
--- a/Objects/descrobject.c
+++ b/Objects/descrobject.c
@@ -226,7 +226,8 @@
         return NULL;
     }
     self = PyTuple_GET_ITEM(args, 0);
-    if (!PyObject_IsInstance(self, (PyObject *)PyDescr_TYPE(descr))) {
+    if (!_PyObject_RealIsSubclass((PyObject *)Py_TYPE(self),
+                                  (PyObject *)PyDescr_TYPE(descr))) {
         PyErr_Format(PyExc_TypeError,
                      "descriptor '%V' "
                      "requires a '%.100s' object "
@@ -284,7 +285,8 @@
         return NULL;
     }
     self = PyTuple_GET_ITEM(args, 0);
-    if (!PyObject_IsInstance(self, (PyObject *)PyDescr_TYPE(descr))) {
+    if (!_PyObject_RealIsSubclass((PyObject *)Py_TYPE(self),
+                                  (PyObject *)PyDescr_TYPE(descr))) {
         PyErr_Format(PyExc_TypeError,
                      "descriptor '%V' "
                      "requires a '%.100s' object "