diff --git a/diff.c b/diff.c
index 528d25ca9c..75ad32ae79 100644
--- a/diff.c
+++ b/diff.c
@@ -13,7 +13,6 @@
 #include "run-command.h"
 #include "utf8.h"
 #include "userdiff.h"
-#include "sigchain.h"
 #include "submodule.h"
 #include "ll-merge.h"
 #include "string-list.h"