diff --git a/src/win32_window.c b/src/win32_window.c
index 8a7211dc..1f58ce6c 100644
--- a/src/win32_window.c
+++ b/src/win32_window.c
@@ -37,6 +37,9 @@
 
 #define _GLFW_WNDCLASSNAME L"GLFW30"
 
+#ifndef GET_XBUTTON_WPARAM
+#define GET_XBUTTON_WPARAM(w) (HIWORD(w))
+#endif
 
 // Returns the window style for the specified window
 //