diff --git a/quiche/http2/adapter/window_manager.h b/quiche/http2/adapter/window_manager.h
index 759a3d3..7005974 100644
--- a/quiche/http2/adapter/window_manager.h
+++ b/quiche/http2/adapter/window_manager.h
@@ -2,6 +2,7 @@
 #define QUICHE_HTTP2_ADAPTER_WINDOW_MANAGER_H_
 
 #include <stddef.h>
+#include <stdint.h>
 
 #include <functional>