diff --git a/ebtree/ebsttree.h b/ebtree/ebsttree.h
index 63ee4f5..87e0306 100644
--- a/ebtree/ebsttree.h
+++ b/ebtree/ebsttree.h
@@ -20,6 +20,9 @@
 
 /* These functions and macros rely on Multi-Byte nodes */
 
+#ifndef _EBSTTREE_H
+#define _EBSTTREE_H
+
 #include "ebtree.h"
 #include "ebmbtree.h"
 
@@ -256,3 +259,5 @@
 	return new;
 }
 
+#endif /* _EBSTTREE_H */
+