diff --git a/ui/ui.h b/ui/ui.h
index f41969b83b..6118ebef68 100644
--- a/ui/ui.h
+++ b/ui/ui.h
@@ -19,6 +19,7 @@
 
 #include "gfx_es2/draw_buffer.h"
 
+#include <string>
 #include <vector>
 
 // Mouse out of habit, applies just as well to touch events.