diff --git a/dlls/ws2_32/socket.c b/dlls/ws2_32/socket.c
index f0e8f2adbce..97cb7db3a62 100644
--- a/dlls/ws2_32/socket.c
+++ b/dlls/ws2_32/socket.c
@@ -624,6 +624,7 @@ static const int ws_flags_map[][2] =
     MAP_OPTION( MSG_PEEK ),
     MAP_OPTION( MSG_DONTROUTE ),
     MAP_OPTION( MSG_WAITALL ),
+    { WS_MSG_PARTIAL, 0 },
 };
 
 static const int ws_sock_map[][2] =