diff --git a/Net/src/SocketImpl.cpp b/Net/src/SocketImpl.cpp
index ce5d6e73c..1b1a65146 100644
--- a/Net/src/SocketImpl.cpp
+++ b/Net/src/SocketImpl.cpp
@@ -32,7 +32,7 @@
 
 
 #ifdef POCO_OS_FAMILY_WINDOWS
-#include <Windows.h>
+#include <windows.h>
 #endif