diff --git a/builtin/checkout.c b/builtin/checkout.c
index 2d72a74..09b8415 100644
--- a/builtin/checkout.c
+++ b/builtin/checkout.c
@@ -21,6 +21,7 @@
 #include "object-store.h"
 #include "parse-options.h"
 #include "preload-index.h"
+#include "read-cache.h"
 #include "refs.h"
 #include "remote.h"
 #include "resolve-undo.h"