diff --git a/Source/Core/Core/Core.h b/Source/Core/Core/Core.h
index 54d6fba56f..e40b9c29ec 100644
--- a/Source/Core/Core/Core.h
+++ b/Source/Core/Core/Core.h
@@ -13,6 +13,7 @@
 #include <memory>
 #include <string>
 #include <string_view>
+#include <optional>
 
 #include "Common/CommonTypes.h"