diff --git a/metadata.h b/metadata.h
index 72eb145..45f5752 100644
--- a/metadata.h
+++ b/metadata.h
@@ -2,8 +2,8 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-#ifndef CHROMEOS_PLATFORM_UPDATE_ENGINE_METADATA_H__
-#define CHROMEOS_PLATFORM_UPDATE_ENGINE_METADATA_H__
+#ifndef CHROMEOS_PLATFORM_UPDATE_ENGINE_METADATA_H_
+#define CHROMEOS_PLATFORM_UPDATE_ENGINE_METADATA_H_
 
 #include "update_engine/delta_diff_generator.h"
 #include "update_engine/graph_types.h"
@@ -34,4 +34,4 @@
 
 };  // namespace chromeos_update_engine
 
-#endif  // CHROMEOS_PLATFORM_UPDATE_ENGINE_METADATA_H__
+#endif  // CHROMEOS_PLATFORM_UPDATE_ENGINE_METADATA_H_