A cleaning device for cleaning windows comprises an elongate wiper element (C) which is robotically controlled to move across the surface of the window to apply and remove cleaning fluid therefrom. The robotic control can be arranged so that the movement of the wiper element corresponds to that which it would follow if used manually by a skilled window cleaner. The wiper element maintains continuous contact with the entire surface of the window without displacement of the wiper from the surface of the window during cleaning.