diff --git a/reactos/include/ddk/unknown.h b/reactos/include/ddk/unknown.h
index fd00a64224f..bbff965ee8c 100644
--- a/reactos/include/ddk/unknown.h
+++ b/reactos/include/ddk/unknown.h
@@ -1,5 +1,5 @@
-#ifndef __unknwn_h__
-#define __unknwn_h__
+#ifndef _UNKNOWN_H_
+#define _UNKNOWN_H_
 
 #ifdef __cplusplus
 extern "C" {
@@ -51,6 +51,5 @@ HRESULT
   IN  PUNKNOWN    OuterUnknown,
   IN  POOL_TYPE   PoolType
 );
-
 #endif