diff --git a/gtk/gtksocket-win32.c b/gtk/gtksocket-win32.c
index 5c96d55f8f..cf57458af3 100644
--- a/gtk/gtksocket-win32.c
+++ b/gtk/gtksocket-win32.c
@@ -39,6 +39,7 @@
 #include "win32/gdkwin32.h"
 
 #include "gtkwin32embed.h"
+#include "gtkwidgetprivate.h"
 
 GdkNativeWindow
 _gtk_socket_windowing_get_id (GtkSocket *socket)