Abstract: A one-piece, linerless, plastic cap for a container. The cap includes an annular top wall section and an integral, generally cylindrical skirt section depending from the top wall. The interior wall of the skirt portion of the cap may be provided with threads for attachment to the threaded neck of a container or with an annular, inwardly projecting bead adapted to be received in a recess in the neck of a container. An integral, flexible, annular sealing ring projects inwardly and downwardly from the underside of the top wall section of the cap and is adapted to make sealing contact with the rim of the neck portion of the container when the cap is secured to the container neck.