diff --git a/src/xenia/ui/graphics_upload_buffer_pool.h b/src/xenia/ui/graphics_upload_buffer_pool.h
index 973a9a6bc..7f5a714d3 100644
--- a/src/xenia/ui/graphics_upload_buffer_pool.h
+++ b/src/xenia/ui/graphics_upload_buffer_pool.h
@@ -10,6 +10,7 @@
 #ifndef XENIA_UI_GRAPHICS_UPLOAD_BUFFER_POOL_H_
 #define XENIA_UI_GRAPHICS_UPLOAD_BUFFER_POOL_H_
 
+#include <cstddef>
 #include <cstdint>
 
 namespace xe {