diff --git a/include/wx/bookctrl.h b/include/wx/bookctrl.h
index 8d5a2a3072..454e99545a 100644
--- a/include/wx/bookctrl.h
+++ b/include/wx/bookctrl.h
@@ -42,6 +42,14 @@ enum
     wxBK_HITTEST_ONPAGE  = 8    // not on tab control, but over the selected page
 };
 
+// wxBookCtrl flags (common for wxNotebook, wxListbook, wxChoicebook, wxTreebook)
+#define wxBK_DEFAULT          0x0000
+#define wxBK_TOP              0x0010
+#define wxBK_BOTTOM           0x0020
+#define wxBK_LEFT             0x0040
+#define wxBK_RIGHT            0x0080
+#define wxBK_ALIGN_MASK       (wxBK_TOP | wxBK_BOTTOM | wxBK_LEFT | wxBK_RIGHT)
+
 // ----------------------------------------------------------------------------
 // wxBookCtrlBase
 // ----------------------------------------------------------------------------