diff --git a/Modules/socketmodule.c b/Modules/socketmodule.c
index 0f56d94..23aab59 100644
--- a/Modules/socketmodule.c
+++ b/Modules/socketmodule.c
@@ -7927,6 +7927,9 @@ PyInit__socket(void)
 #ifdef  IPPROTO_BIP
     PyModule_AddIntMacro(m, IPPROTO_BIP);
 #endif
+#ifdef  IPPROTO_MPTCP
+    PyModule_AddIntMacro(m, IPPROTO_MPTCP);
+#endif
 /**/
 #ifdef  IPPROTO_RAW
     PyModule_AddIntMacro(m, IPPROTO_RAW);