diff --git a/alias.h b/alias.h
index 79933f2457c..aef4843bb78 100644
--- a/alias.h
+++ b/alias.h
@@ -1,5 +1,5 @@
-#ifndef __ALIAS_H__
-#define __ALIAS_H__
+#ifndef ALIAS_H
+#define ALIAS_H
 
 struct string_list;
 
diff --git a/commit-reach.h b/commit-reach.h
index 7d313e2975a..122a23a24d8 100644
--- a/commit-reach.h
+++ b/commit-reach.h
@@ -1,5 +1,5 @@
-#ifndef __COMMIT_REACH_H__
-#define __COMMIT_REACH_H__
+#ifndef COMMIT_REACH_H
+#define COMMIT_REACH_H
 
 #include "commit-slab.h"
 
diff --git a/fetch-negotiator.h b/fetch-negotiator.h
index ddb44a22dce..9e3967ce662 100644
--- a/fetch-negotiator.h
+++ b/fetch-negotiator.h
@@ -1,5 +1,5 @@
-#ifndef FETCH_NEGOTIATOR
-#define FETCH_NEGOTIATOR
+#ifndef FETCH_NEGOTIATOR_H
+#define FETCH_NEGOTIATOR_H
 
 struct commit;
 
diff --git a/midx.h b/midx.h
index 2d7c9c6cd1d..1d6c21afe31 100644
--- a/midx.h
+++ b/midx.h
@@ -1,5 +1,5 @@
-#ifndef __MIDX_H__
-#define __MIDX_H__
+#ifndef MIDX_H
+#define MIDX_H
 
 #include "repository.h"
 
diff --git a/t/helper/test-tool.h b/t/helper/test-tool.h
index e4890566da5..71f470b8714 100644
--- a/t/helper/test-tool.h
+++ b/t/helper/test-tool.h
@@ -1,5 +1,5 @@
-#ifndef __TEST_TOOL_H__
-#define __TEST_TOOL_H__
+#ifndef TEST_TOOL_H
+#define TEST_TOOL_H
 
 #include "git-compat-util.h"
 
diff --git a/vcs-svn/fast_export.h b/vcs-svn/fast_export.h
index 60b79c35b97..9dcf9337c18 100644
--- a/vcs-svn/fast_export.h
+++ b/vcs-svn/fast_export.h
@@ -1,5 +1,5 @@
-#ifndef FAST_EXPORT_H_
-#define FAST_EXPORT_H_
+#ifndef FAST_EXPORT_H
+#define FAST_EXPORT_H
 
 struct strbuf;
 struct line_buffer;
diff --git a/vcs-svn/line_buffer.h b/vcs-svn/line_buffer.h
index ee23b4f4902..e192aedea29 100644
--- a/vcs-svn/line_buffer.h
+++ b/vcs-svn/line_buffer.h
@@ -1,5 +1,5 @@
-#ifndef LINE_BUFFER_H_
-#define LINE_BUFFER_H_
+#ifndef LINE_BUFFER_H
+#define LINE_BUFFER_H
 
 #include "strbuf.h"
 
diff --git a/vcs-svn/sliding_window.h b/vcs-svn/sliding_window.h
index b43a825cbab..189c32d84c3 100644
--- a/vcs-svn/sliding_window.h
+++ b/vcs-svn/sliding_window.h
@@ -1,5 +1,5 @@
-#ifndef SLIDING_WINDOW_H_
-#define SLIDING_WINDOW_H_
+#ifndef SLIDING_WINDOW_H
+#define SLIDING_WINDOW_H
 
 #include "strbuf.h"
 
diff --git a/vcs-svn/svndiff.h b/vcs-svn/svndiff.h
index 74eb464bab2..10a2cbc40ec 100644
--- a/vcs-svn/svndiff.h
+++ b/vcs-svn/svndiff.h
@@ -1,5 +1,5 @@
-#ifndef SVNDIFF_H_
-#define SVNDIFF_H_
+#ifndef SVNDIFF_H
+#define SVNDIFF_H
 
 struct line_buffer;
 struct sliding_view;
diff --git a/vcs-svn/svndump.h b/vcs-svn/svndump.h
index b8eb12954e8..26faed59684 100644
--- a/vcs-svn/svndump.h
+++ b/vcs-svn/svndump.h
@@ -1,5 +1,5 @@
-#ifndef SVNDUMP_H_
-#define SVNDUMP_H_
+#ifndef SVNDUMP_H
+#define SVNDUMP_H
 
 int svndump_init(const char *filename);
 int svndump_init_fd(int in_fd, int back_fd);