diff --git a/include/SDL_syswm.h b/include/SDL_syswm.h
index c1022c15f..715f2c058 100644
--- a/include/SDL_syswm.h
+++ b/include/SDL_syswm.h
@@ -52,7 +52,9 @@ struct SDL_SysWMinfo;
 #else
 
 #if defined(SDL_VIDEO_DRIVER_WINDOWS)
+#ifndef WIN32_LEAN_AND_MEAN
 #define WIN32_LEAN_AND_MEAN
+#endif
 #include <windows.h>
 #endif