diff --git a/sys/netinet/tcp_debug.c b/sys/netinet/tcp_debug.c
index 89e9d7cbc94..203cc3c642c 100644
--- a/sys/netinet/tcp_debug.c
+++ b/sys/netinet/tcp_debug.c
@@ -51,6 +51,7 @@
 #endif
 
 #include <sys/param.h>
+#include <sys/mac.h>
 #include <sys/systm.h>
 #include <sys/protosw.h>
 #include <sys/socket.h>