diff --git a/Userland/Libraries/LibC/netinet/tcp.h b/Userland/Libraries/LibC/netinet/tcp.h
index 57de6cbdbf..219e5c8fa1 100644
--- a/Userland/Libraries/LibC/netinet/tcp.h
+++ b/Userland/Libraries/LibC/netinet/tcp.h
@@ -7,3 +7,4 @@
 #pragma once
 
 #define TCP_NODELAY 10
+#define TCP_MAXSEG 11