- Directors: Tom Shadyac
- Producers: Brian Grazer
- Writers: Paul Guay, Stephen Mazur
- Genres: Comedy, Fantasy
- Actors: Jim Carrey, Maura Tierney, Justin Cooper, Jennifer Tilly, Anne Haney, Swoosie Kurtz, Cary Elwes, Amanda Donohoe
Fletcher Reede (Jim Carrey) is a particularly career-focused lawyer and divorced father. He has a habit of giving precedence to his job, breaking promises to his young son Max, and then lying to both Max (Justin Cooper) and his ex-wife Audrey (Maura Tierney) about the real reason for having done so. Ultimately, Fletcher misses his son’s birthday party because he is having sex with his partner Miranda (Amanda Donohoe), and Max wishes while blowing out his cake candles that his father couldn’t tell a lie for an entire day, a wish that immediately becomes true.
Fletcher soon discovers, through a series of embarrassing incidentsâ€”such as when he tells Miranda that he has “had better” just after having sex with herâ€”that he is unable to lie or even withhold a true answer. These incidents are inconvenient, as he is fighting a divorce case in court which, should he win, could be a huge boost to his career. His client is Samantha Cole (Jennifer Tilly). His main witness is willing to commit perjury to win, but Fletcher discovers that he cannot even ask a question if he knows the answer will be a lie; during the case he even objects to himself when he tries to lie to get the desired information. Meanwhile, Audrey is threatening to move to Boston with her new boyfriend Jerry (Cary Elwes) and to take Max with them.
The premise of Liar Liar, that of a protagonist who must tell the truth for the next 24 hours, can also be found in the Bob Hope movie Nothing But the Truth (1941 film).