Abstract: A closure for a container characterized by a crown and a depending skirt, retaining means provided on the skirt adapted to cooperate with corresponding means on a container to retain the closure about a neck of the container defining a dispensing opening thereof, a flexible annular sealing ring extending from an internal surface of the closure adapted to engage in sealing relationship with the container neck, a sealing ring support adapted to assist said ring into sealing engagement with the container and means for permitting pressure of the container contents to act upon the sealing ring to urge the ring into sealing engagement with the neck of the container to which the closure is applied.