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.

Sir William Schwenck Gilbert was an English dramatist, librettist, poet and illustrator best known for his collaboration with composer Arthur Sullivan, which produced fourteen comic operas. The most famous of these include H.M.S. Pinafore, The Pirates of Penzance and one of the most frequently performed works in the history of musical theatre, The Mikado. The popularity of these works was supported for over a century by year-round performances of them, in Britain and abroad, by the repertory company that Gilbert, Sullivan and their producer Richard D'Oyly Carte founded, the D'Oyly Carte Opera Company. These Savoy operas are still frequently performed in the English-speaking world and beyond.