diff --git a/include/wx/sizer.h b/include/wx/sizer.h
index 28965fe97e..410b2c1e37 100644
--- a/include/wx/sizer.h
+++ b/include/wx/sizer.h
@@ -18,7 +18,6 @@
 #include "wx/window.h"
 #include "wx/frame.h"
 #include "wx/dialog.h"
-#include "wx/bookctrl.h"
 
 //---------------------------------------------------------------------------
 // classes