diff --git a/examples/imgui_impl_win32.cpp b/examples/imgui_impl_win32.cpp
index 86873084..e713b8d3 100644
--- a/examples/imgui_impl_win32.cpp
+++ b/examples/imgui_impl_win32.cpp
@@ -8,7 +8,9 @@
 
 #include "imgui.h"
 #include "imgui_impl_win32.h"
+#ifndef WIN32_LEAN_AND_MEAN
 #define WIN32_LEAN_AND_MEAN
+#endif
 #include <windows.h>
 #include <tchar.h>