diff --git a/diff.h b/diff.h
index b90036f529..f80bd297ca 100644
--- a/diff.h
+++ b/diff.h
@@ -6,7 +6,6 @@
 
 #include "tree-walk.h"
 #include "pathspec.h"
-#include "object.h"
 #include "oidset.h"
 #include "strbuf.h"