diff --git a/etc/mtree/BSD.include.dist b/etc/mtree/BSD.include.dist
index f2597ba65052..22bbaa73662e 100644
--- a/etc/mtree/BSD.include.dist
+++ b/etc/mtree/BSD.include.dist
@@ -228,6 +228,8 @@
         ..
         netdump
         ..
+        tcp_stacks
+        ..
     ..
     netinet6
     ..
diff --git a/include/Makefile b/include/Makefile
index 2f82b6744eac..91ad90e2c402 100644
--- a/include/Makefile
+++ b/include/Makefile
@@ -57,6 +57,7 @@ LSUBDIRS=	cam/ata cam/mmc cam/nvme cam/scsi \
 	netgraph/atm netgraph/netflow \
 	netinet/cc \
 	netinet/netdump \
+	netinet/tcp_stacks \
 	security/audit \
 	security/mac_biba security/mac_bsdextended security/mac_lomac \
 	security/mac_mls security/mac_partition \