A Funny Thing Happened on the Way to the Forum is a musical with music and lyrics by Stephen Sondheim and a book by Burt Shevelove and Larry Gelbart.

Based on the comedies of the ancient Roman playwright Plautus, it tells the story of a slave named Pseudolus and his attempts to win his freedom by encouraging the romance between his master's son Hero and a young virgin named Philia who is owned by Marcus Lycus, a dealer in courtesans, and promised to a swaggering soldier named Miles Gloriosus. The humor is broad and bawdy and fast-paced.

Sondheim's score was coolly received when Forum opened on Broadway on May 8, 1962, at the Alvin Theatre, and the score was not even nominated for a Tony Award even though the show won the award for Best Musical. Starring Zero Mostel, Jack Gilford, David Burns, Ruth Kobart, and John Carradine (who was replaced by Erik Rhodes), the original production was directed by Broadway legend George Abbott and played 966 performances--Sondheim's longest Broadway run to date.

A Funny Thing Happened on the Way to the Forum was made into a film in 1966 with Zero Mostel, Jack Gilford, Buster Keaton, a very young Michael Crawford and Phil Silvers (who also starred in a critically well-received Broadway revival in 1972). It was also revived with great success in 1996 with Nathan Lane as Pseudolus, replaced later in the run by Whoopi Goldberg, and also David Alan Grier.

Characters

• Pseudolus – A Roman slave, owned by Hero, who seeks to win his freedom by helping his young master win the heart of a virgin in the house of Marcus Lycus.
• Hero – Young son of Senex who falls in love with the virgin, Philia.
• Philia – A virgin in the house of Marcus Lycus, and Hero's love interest.
• Senex – A Roman Senator living in a less fashionable suburb of Rome.
• Marcus Lycus – A purveyor of courtesans, who operates from the house to the left of Senex.
• Domina – The wife of Senex.
• Erronius – The elderly neighbor to the right of Senex who is searching for his two children, kidnapped in infancy by pirates.
• Gymnasia – A mute courtesan from the house of Senex (she is mute only in the film).
• Miles Gloriosus – A conceited captain in the Roman army.
• Hysterium – The chief slave in the house of Senex.
• Fertilla the Populator – A female "Breeding Slave" (film only).
• Crassus – A merchant at the docks (film only).
• Tintinabula – A courtesan in the house of Lycus.
• Vibratta – A courtesan in the house of Lycus.
• Gemini – Twin courtesans in the house of Lycus.
• Panacea – A courtesan in the house of Lycus.
• Domina's Mother – Senex's whip-wielding mother-in-law (talked of in the play but seen only in the film).