Apparatus is provided for automatically lidding drinking cups with a film of thermoplastic sheet material. The apparatus includes a cup support adapted to raise a cup placed thereon into contact with a leading section of thermoplastic film drawn from a roll and to hold the cup while a reciprocating heated platen heat seals the film section against the cup rim. The cup support then lowers the lidded cup while a film advance mechanism draws out a fresh section of film into sealing position. A control system is included with the apparatus for operating the apparatus in predetermined timed sequence.