diff --git a/include/ntapi/nt_socket.h b/include/ntapi/nt_socket.h
index 4b7e783..aceb781 100644
--- a/include/ntapi/nt_socket.h
+++ b/include/ntapi/nt_socket.h
@@ -221,6 +221,9 @@
 #define NT_AFD_IOCTL_GET_INFO			(0x1207bu)
 #define NT_AFD_IOCTL_SOCKOPT			(0x120bfu)
 
+/* afd listen/accept bits */
+#define NT_AFD_DEFER_ACCEPT			(0x01u)
+
 /* afd sockopt mode bits */
 #define NT_AFD_SOCKOPT_SET			(0x01u)
 #define NT_AFD_SOCKOPT_GET			(0x02u)