diff --git a/include/renderer_mtl/objc_helper.hpp b/include/renderer_mtl/objc_helper.hpp
index d00682e4..91756d24 100644
--- a/include/renderer_mtl/objc_helper.hpp
+++ b/include/renderer_mtl/objc_helper.hpp
@@ -1,5 +1,7 @@
 #pragma once
 
+#include <string>
+
 #include <Metal/Metal.hpp>
 
 namespace Metal {