Trial by Jury is a comic opera in one act, with music by Arthur Sullivan and libretto by W. S. Gilbert. It was first produced on 25 March 1875, at London's Royalty Theatre, where it initially ran for 131 performances and was considered a hit, receiving critical praise and outrunning its popular companion piece, Jacques Offenbach's La Périchole. The story concerns a "breach of promise of marriage" lawsuit in which the judge and legal system are the objects of lighthearted satire. Gilbert based the libretto of Trial by Jury on an operetta parody that he had written in 1868.

Comic opera, sometimes known as light opera, is a sung dramatic work of a light or comic nature, usually with a happy ending and often including spoken dialogue.