diff --git a/policy_manager/provider.h b/policy_manager/provider.h
index 170c4c4..9ee5e8a 100644
--- a/policy_manager/provider.h
+++ b/policy_manager/provider.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_POLICY_MANAGER_PROVIDER_H
-#define CHROMEOS_PLATFORM_UPDATE_ENGINE_POLICY_MANAGER_PROVIDER_H
+#ifndef CHROMEOS_PLATFORM_UPDATE_ENGINE_POLICY_MANAGER_PROVIDER_H_
+#define CHROMEOS_PLATFORM_UPDATE_ENGINE_POLICY_MANAGER_PROVIDER_H_
 
 namespace chromeos_policy_manager {
 
@@ -32,4 +32,4 @@
 
 }  // namespace chromeos_policy_manager
 
-#endif  // CHROMEOS_PLATFORM_UPDATE_ENGINE_POLICY_MANAGER_PROVIDER_H
+#endif  // CHROMEOS_PLATFORM_UPDATE_ENGINE_POLICY_MANAGER_PROVIDER_H_