diff --git a/diffcore.h b/diffcore.h
index 1ea80671e3..7b9294eab2 100644
--- a/diffcore.h
+++ b/diffcore.h
@@ -1,8 +1,8 @@
 /*
  * Copyright (C) 2005 Junio C Hamano
  */
-#ifndef _DIFFCORE_H_
-#define _DIFFCORE_H_
+#ifndef DIFFCORE_H
+#define DIFFCORE_H
 
 /* This header file is internal between diff.c and its diff transformers
  * (e.g. diffcore-rename, diffcore-pickaxe).  Never include this header
diff --git a/exec_cmd.h b/exec_cmd.h
index 989621ff4e..849a8395a0 100644
--- a/exec_cmd.h
+++ b/exec_cmd.h
@@ -1,5 +1,5 @@
-#ifndef __GIT_EXEC_CMD_H_
-#define __GIT_EXEC_CMD_H_
+#ifndef GIT_EXEC_CMD_H
+#define GIT_EXEC_CMD_H
 
 extern void git_set_exec_path(const char *exec_path);
 extern const char* git_exec_path(void);
@@ -7,4 +7,4 @@ extern int execv_git_cmd(const char **argv); /* NULL terminated */
 extern int execl_git_cmd(const char *cmd, ...);
 
 
-#endif /* __GIT_EXEC_CMD_H_ */
+#endif /* GIT_EXEC_CMD_H */
diff --git a/path-list.h b/path-list.h
index d6401eaa35..ce5ffabcce 100644
--- a/path-list.h
+++ b/path-list.h
@@ -1,5 +1,5 @@
-#ifndef _PATH_LIST_H_
-#define _PATH_LIST_H_
+#ifndef PATH_LIST_H
+#define PATH_LIST_H
 
 struct path_list_item {
 	char *path;
@@ -19,4 +19,4 @@ void path_list_clear(struct path_list *list, int free_items);
 struct path_list_item *path_list_insert(const char *path, struct path_list *list);
 struct path_list_item *path_list_lookup(const char *path, struct path_list *list);
 
-#endif /* _PATH_LIST_H_ */
+#endif /* PATH_LIST_H */
diff --git a/progress.h b/progress.h
index 4ee851acfb..5ae1a89e5a 100644
--- a/progress.h
+++ b/progress.h
@@ -1,5 +1,5 @@
-#ifndef __progress_h__
-#define __progress_h__
+#ifndef PROGRESS_H
+#define PROGRESS_H
 
 struct progress {
 	const char *prefix;