diff --git a/demo/gdi_native_nuklear/main.c b/demo/gdi_native_nuklear/main.c
index b6cb6a9..349adea 100644
--- a/demo/gdi_native_nuklear/main.c
+++ b/demo/gdi_native_nuklear/main.c
@@ -1,4 +1,4 @@
-#include <Windows.h>
+#include <windows.h>
 
 #pragma comment(linker,"\"/manifestdependency:type='win32' \
 name='Microsoft.Windows.Common-Controls' version='6.0.0.0' \
diff --git a/demo/gdi_native_nuklear/window.h b/demo/gdi_native_nuklear/window.h
index 0db572f..f78d574 100644
--- a/demo/gdi_native_nuklear/window.h
+++ b/demo/gdi_native_nuklear/window.h
@@ -3,7 +3,7 @@
 
 #define NK_GDI_WINDOW_CLS L"WNDCLS_NkGdi"
 
-#include <Windows.h>
+#include <windows.h>
 
 /* Functin pointer types for window callbacks */
 typedef int(*nkgdi_window_func_close)(void);