diff --git a/intern/ghost/intern/GHOST_SizerWin32.cpp b/intern/ghost/intern/GHOST_SizerWin32.cpp
index 9aa9ba313e6..a66840f8bd5 100644
--- a/intern/ghost/intern/GHOST_SizerWin32.cpp
+++ b/intern/ghost/intern/GHOST_SizerWin32.cpp
@@ -32,7 +32,7 @@
 
 
 #include "GHOST_SizerWin32.h"
-#include <Windowsx.h>
+#include <windowsx.h>
 
 #define T_NONE (0)
 #define T_SIZE (1)