diff -r 50d93fe73726 Lib/test/test_socket.py
--- a/Lib/test/test_socket.py	Tue May 27 03:31:32 2014 -0400
+++ b/Lib/test/test_socket.py	Tue May 27 20:00:58 2014 +0700
@@ -19,6 +19,7 @@
 import math
 import pickle
 import struct
+import pydoc
 try:
     import multiprocessing
 except ImportError:
@@ -4974,6 +4975,17 @@
         socket.setdefaulttimeout(t)
 
 
+class TestSocketPyDoc(unittest.TestCase):
+
+    # issue 20689
+    def test_pydoc_display_AddressFamily(self):
+        with support.captured_stdout() as help_io:
+            pydoc.help(socket)
+        helptext = help_io.getvalue()
+        # Should we test all classes and exceptions?
+        self.assertIn('class AddressFamily', helptext)
+
+
 @unittest.skipUnless(os.name == "nt", "Windows specific")
 @unittest.skipUnless(multiprocessing, "need multiprocessing")
 class TestSocketSharing(SocketTCPTest):
@@ -5128,6 +5140,7 @@
         # These are slow when setitimer() is not available
         InterruptedRecvTimeoutTest,
         InterruptedSendTimeoutTest,
+        TestSocketPyDoc,
         TestSocketSharing,
     ])
 
diff -r 50d93fe73726 Modules/socketmodule.c
--- a/Modules/socketmodule.c	Tue May 27 03:31:32 2014 -0400
+++ b/Modules/socketmodule.c	Tue May 27 20:00:58 2014 +0700
@@ -5817,6 +5817,10 @@
     if (PyModule_AddObject(m, "socket",
                            (PyObject *)&sock_type) != 0)
         return NULL;
+    Py_INCREF((PyObject *)&sock_type);
+    if (PyModule_AddObject(m, "AddressFamily",
+                           (PyObject *)&sock_type) != 0)
+        return NULL;
 
 #ifdef ENABLE_IPV6
     has_ipv6 = Py_True;