diff --git a/test cases/windows/1 basic/prog.c b/test cases/windows/1 basic/prog.c
index 8703980e7..58162a49f 100644
--- a/test cases/windows/1 basic/prog.c	
+++ b/test cases/windows/1 basic/prog.c	
@@ -1,4 +1,4 @@
-#include <Windows.h>
+#include <windows.h>
 
 int main(int argc, char **argv) {
     return 0;