Abstract: A straw-insertable disposable lid is disclosed including a flexible disk-like body having a top surface for covering an opening of a cup, a plurality of intersecting lines of weakness each extending between two ends with the lines of weakness being located on the body and adapted to permit the insertion of a drinking straw through the top surface of the lid and a plurality of intersecting troughs for accommodating a respective one of the intersecting lines of weakness, with the troughs acting to stop the propagation of the tearing of the lines of weakness in a radially outward direction when a straw is inserted into the lid and for closing the plurality of intersecting lines of weakness in response to a fluid pressure force acting on an underside of the top surface of the lid should a filled cup incorporating such lid be inadvertently tilted over.