diff --git a/show-diff.c b/show-diff.c
index 0af2f1051e4..8a66e59cf5f 100644
--- a/show-diff.c
+++ b/show-diff.c
@@ -4,7 +4,6 @@
  * Copyright (C) Linus Torvalds, 2005
  */
 #include "cache.h"
-#include <ctype.h>
 
 static char *diff_cmd = "diff -L '%s' -u -N  - '%s'";