diff --git a/include/wx/sizer.h b/include/wx/sizer.h
index 993647edc7..ece3be312e 100644
--- a/include/wx/sizer.h
+++ b/include/wx/sizer.h
@@ -323,6 +323,9 @@ public:
     int GetOrientation()
         { return m_orient; }
 
+    void SetOrientation(int orient)
+        { m_orient = orient; }
+
 protected:
     int m_orient;
     int m_stretchable;