Jack's Graduation is the 25th and final episode of season four of Three's Company, and the 78th overall episode of the series. Co-written by Michael S. Baser and Kim Weiskopf and directed by Dave Powers, it first aired 6 May 1980 on ABC.
During Jack's final cooking exam, another student, Ben Baxter, switches his dish with Jack's. Jack thinks he has failed and can't graduate. He finally figures out what happened but must get Ben to confess in front of Dean Travers. The girls invite Ben and Dean Travers to the apartment and Chrissy tricks Ben into admitting what he did. Jack will graduate, and with honors.