diff --git a/hash/md5.hpp b/hash/md5.hpp
index 58679232..1cfb1de0 100644
--- a/hash/md5.hpp
+++ b/hash/md5.hpp
@@ -14,8 +14,8 @@
  * Copyright 2013 Danny Robson <danny@nerdcruft.net>
  */
 
-#ifndef __UTIL_MD5_HPP
-#define __UTIL_MD5_HPP
+#ifndef __UTIL_HASH_MD5_HPP
+#define __UTIL_HASH_MD5_HPP
 
 #include <array>
 #include <cstdint>