diff --git a/sys/netinet/tcp_ecn.c b/sys/netinet/tcp_ecn.c
--- a/sys/netinet/tcp_ecn.c
+++ b/sys/netinet/tcp_ecn.c
@@ -98,7 +98,6 @@
 #include <netinet/tcp_var.h>
 #include <netinet/tcp_syncache.h>
 #include <netinet/tcp_timer.h>
-#include <netinet6/tcp6_var.h>
 #include <netinet/tcpip.h>
 #include <netinet/tcp_ecn.h>
 
diff --git a/sys/netinet/tcp_ratelimit.c b/sys/netinet/tcp_ratelimit.c
--- a/sys/netinet/tcp_ratelimit.c
+++ b/sys/netinet/tcp_ratelimit.c
@@ -54,9 +54,6 @@
 #include <netinet/in_pcb.h>
 #define TCPSTATES		/* for logging */
 #include <netinet/tcp_var.h>
-#ifdef INET6
-#include <netinet6/tcp6_var.h>
-#endif
 #include <netinet/tcp_hpts.h>
 #include <netinet/tcp_log_buf.h>
 #include <netinet/tcp_ratelimit.h>
diff --git a/sys/netinet/tcp_reass.c b/sys/netinet/tcp_reass.c
--- a/sys/netinet/tcp_reass.c
+++ b/sys/netinet/tcp_reass.c
@@ -80,7 +80,6 @@
 #include <netinet/tcp_log_buf.h>
 #include <netinet/tcp_hpts.h>
 #endif
-#include <netinet6/tcp6_var.h>
 #include <netinet/tcpip.h>
 #ifdef TCPDEBUG
 #include <netinet/tcp_debug.h>
diff --git a/sys/netinet/tcp_sack.c b/sys/netinet/tcp_sack.c
--- a/sys/netinet/tcp_sack.c
+++ b/sys/netinet/tcp_sack.c
@@ -117,7 +117,6 @@
 #include <netinet/tcp_seq.h>
 #include <netinet/tcp_timer.h>
 #include <netinet/tcp_var.h>
-#include <netinet6/tcp6_var.h>
 #include <netinet/tcpip.h>
 #include <netinet/cc/cc.h>
 #ifdef TCPDEBUG
diff --git a/sys/netinet/tcp_syncache.c b/sys/netinet/tcp_syncache.c
--- a/sys/netinet/tcp_syncache.c
+++ b/sys/netinet/tcp_syncache.c
@@ -90,9 +90,6 @@
 #include <netinet/tcp_var.h>
 #include <netinet/tcp_syncache.h>
 #include <netinet/tcp_ecn.h>
-#ifdef INET6
-#include <netinet6/tcp6_var.h>
-#endif
 #ifdef TCP_OFFLOAD
 #include <netinet/toecore.h>
 #endif
diff --git a/sys/netinet/tcp_timewait.c b/sys/netinet/tcp_timewait.c
--- a/sys/netinet/tcp_timewait.c
+++ b/sys/netinet/tcp_timewait.c
@@ -82,9 +82,6 @@
 #include <netinet/tcp_timer.h>
 #include <netinet/tcp_var.h>
 #include <netinet/tcp_hpts.h>
-#ifdef INET6
-#include <netinet6/tcp6_var.h>
-#endif
 #include <netinet/tcpip.h>
 #ifdef TCPDEBUG
 #include <netinet/tcp_debug.h>