Abstract: A valve for use with a cap for a spill resistant cup, the cap including a spout to dispense the liquid and a valve mount extending from the spout to engage with the valve. The valve includes a generally cylindrical valve tower extending from a valve base to sealingly engage the valve mount and having an interior bore for the passage of liquid and a valve face sloping across an upper end of the valve tower bore from a higher first point on a first side of the valve tower and to a lower second point on a diametrically opposite second side of the valve tower. A valve mechanism is located in the valve face for controlling a flow of the liquid through the valve mechanism dependent upon a pressure differential across the valve face. The valve mechanism is a valve slit extending through the valve face perpendicular to a mouth opening in the spout and is S-shaped or straight.