A two-piece rotary dispensing cap for a jar or container containing granular or powdered material comprises a cylindrical cap body having one end threaded for connection to the mouth of the jar or container and a relatively rotatable metering disk member overlying the cap body formed with one or more discharge openings through which material is dispensed exterior of the jar or container. The cap body is formed with an enclosed collection chamber having upper and lower open ends. The upper end faces the exterior of the container and the lower end is exposed in and directly communicates with the interior contents of the jar or container. The disk member is formed with a rotatable shaft received in the cap body and formed at its interior, lower end with a planar valve plate. The valve plate is disposed to directly underlie one of the discharge openings formed in the disk member and serves to block off flow communication between the lower open end of the collection chamber and the interior of the jar or container when material previously collected in the chamber is being dispensed through the chamber upper end and that one opening in the disk member.