Falstaff is an operatic commedia lirica in three acts by Giuseppe Verdi, adapted by Arrigo Boito from Shakespeare's plays The Merry Wives of Windsor and scenes from Henry IV. It was Verdi's last opera, written in the composer's ninth decade, and only the second of his 26 operas to be a comedy. It was also the third of Verdi's operas to be based on a Shakespearean play, following his earlier Macbeth and Otello. (Verdi had toyed, too, with writing an opera based on King Lear and Arrigo Boito later tried to interest him in Antony and Cleopatra, but neither project was ever brought to fruition.)

While it has not proved to be as immensely popular as the Verdi works that immediately preceded it, namely Aida and Otello, Falstaff has long been an admired favorite with critics and musicians because of its brilliant orchestration, scintillating libretto and refined melodic invention. It is in the standard repertoire of many opera companies.

The first performance of Falstaff took place on 9 February 1893 at La Scala, Milan to great success. The illustrious French baritone Victor Maurel, who had created the role of Iago in Verdi's previous opera, Otello, sang Falstaff at the premiere.

Sir John Falstaff is a fictional character who appears in three plays by William Shakespeare. In the two Henry IV plays, he is a companion to Prince Hal, the future King Henry V. A fat, vain, boastful, and cowardly knight, Falstaff leads the apparently wayward Prince Hal into trouble, and is ultimately repudiated after Hal becomes king. Falstaff also appears in The Merry Wives of Windsor.

Though primarily a comic figure, Falstaff still embodies a kind of depth common to Shakespeare's tricky comedy. In Act II, Scene III of Henry V, his death is described by the character "Hostess", possibly the Mistress Quickly of Henry IV, who describes his body in terms that parody Plato's description of the death of Socrates.

He appears in the following plays:

His death is mentioned in Henry V but he has no lines, nor is it directed that he appear on stage. However, many stage and film adaptations have seen it necessary to include Falstaff for the insight he provides into King Henry V's character. The most notable examples in cinema are Laurence Olivier's 1944 version and Kenneth Branagh's 1989 film, both of which draw additional material from the Henry IV plays.

Opera (English plural: operas; Italian plural: opere) is an art form in which singers and musicians perform a dramatic work combining text (called a libretto) and musical score, usually in a theatrical setting. Opera incorporates many of the elements of spoken theatre, such as acting, scenery, and costumes and sometimes includes dance. The performance is typically given in an opera house, accompanied by an orchestra or smaller musical ensemble.

Opera is part of the Western classical music tradition. It started in Italy at the end of the 16th century (with Jacopo Peri's lost Dafne, produced in Florence around 1597) and soon spread through the rest of Europe: Schütz in Germany, Lully in France, and Purcell in England all helped to establish their national traditions in the 17th century. In the 18th century, Italian opera continued to dominate most of Europe, except France, attracting foreign composers such as Handel. Opera seria was the most prestigious form of Italian opera, until Gluck reacted against its artificiality with his "reform" operas in the 1760s. Today the most renowned figure of late 18th century opera is Mozart, who began with opera seria but is most famous for his Italian comic operas, especially The Marriage of Figaro, Don Giovanni, and Così fan tutte, as well as The Magic Flute, a landmark in the German tradition.