The Pirates of Penzance, or The Slave of Duty, is a comic opera in two acts. One of the Savoy Operas, the official premiere was at the Fifth Avenue Theatre in New York on December 31, 1879, where it was a hit with audiences and critics. The London premiere was on April 3, 1880, at the Opera Comique, where it ran for 363 performances, having already been playing successfully for over three months in New York.

Pirates remains popular today, taking its place along with The Mikado and H.M.S. Pinafore as one of the most frequently played Gilbert and Sullivan operas. Its successful 1981 Broadway revival by Joseph Papp refreshed its popularity.