diff --git a/Kernel/UnixTypes.h b/Kernel/UnixTypes.h
index 5b89a5f751..a8923b2032 100644
--- a/Kernel/UnixTypes.h
+++ b/Kernel/UnixTypes.h
@@ -379,6 +379,7 @@ struct pollfd {
 #define AF_UNSPEC 0
 #define AF_LOCAL 1
 #define AF_INET 2
+#define AF_MAX 3
 #define PF_LOCAL AF_LOCAL
 #define PF_INET AF_INET
 
diff --git a/Libraries/LibC/sys/socket.h b/Libraries/LibC/sys/socket.h
index 92c08d8652..2e98f47865 100644
--- a/Libraries/LibC/sys/socket.h
+++ b/Libraries/LibC/sys/socket.h
@@ -38,10 +38,12 @@ __BEGIN_DECLS
 #define AF_LOCAL 1
 #define AF_UNIX AF_LOCAL
 #define AF_INET 2
+#define AF_MAX 3
 #define PF_LOCAL AF_LOCAL
 #define PF_UNIX PF_LOCAL
 #define PF_INET AF_INET
 #define PF_UNSPEC AF_UNSPEC
+#define PF_MAX AF_MAX
 
 #define SOCK_TYPE_MASK 0xff
 #define SOCK_STREAM 1