diff --git a/portable/MSVC-MingW/portmacro.h b/portable/MSVC-MingW/portmacro.h
index 83b13b19e..38128785e 100644
--- a/portable/MSVC-MingW/portmacro.h
+++ b/portable/MSVC-MingW/portmacro.h
@@ -28,8 +28,8 @@
 #ifndef PORTMACRO_H
 #define PORTMACRO_H
 
-#include <Windows.h>
-#include <WinBase.h>
+#include <windows.h>
+#include <winbase.h>
 
 /******************************************************************************
 	Defines