diff --git a/Source/Core/Core/IOS/IOSC.h b/Source/Core/Core/IOS/IOSC.h
index 7b3bc2d86f..773fba36c4 100644
--- a/Source/Core/Core/IOS/IOSC.h
+++ b/Source/Core/Core/IOS/IOSC.h
@@ -7,7 +7,7 @@
 #pragma once
 
 #include <array>
-#include <map>
+#include <cstddef>
 #include <vector>
 
 #include "Common/CommonTypes.h"