diff --git a/lib/zebra.h b/lib/zebra.h
index 0a61c433d9..2cc433a863 100644
--- a/lib/zebra.h
+++ b/lib/zebra.h
@@ -126,6 +126,8 @@ typedef unsigned char   u_int8_t;
 #define __APPLE_USE_RFC_3542
 #endif
 
+#include "lib/openbsd-tree.h"
+
 #include <netinet/in.h>
 #include <netinet/in_systm.h>
 #include <netinet/ip.h>