Abstract: A closure system comprising a container having a neck with external threads thereon and a cap having an end wall, an annular skirt and a dispensing opening extending through the end wall. The skirt has internal threads complimentary to the external threads on the container neck for selectively screwing the cap onto the container neck. Cooperating locking members are provided on the outer surface of the container neck and on the inner surface of the skirt, the locking members preventing rotation of the cap. In one embodiment, a tear out section is provided on the cap skirt which is torn when an attempt is made to unscrew the cap from the container. In another embodiment of the closure system, the locking members are used in association with a non-cylindrical container and a non-cylindrical cap to position the dispensing opening relative to the container in a predetermined position.