diff --git a/ports/unix/modsocket.c b/ports/unix/modsocket.c
index 6d6059ae4..2aaa21183 100644
--- a/ports/unix/modsocket.c
+++ b/ports/unix/modsocket.c
@@ -701,6 +701,7 @@ static const mp_rom_map_elem_t mp_module_socket_globals_table[] = {
 
     C(MSG_DONTROUTE),
     C(MSG_DONTWAIT),
+    C(MSG_PEEK),
 
     C(SOL_SOCKET),
     C(SO_BROADCAST),