• Ruggero Leoncavallo. Dramma in a prologue and two acts. 1892.
• Libretto by the composer.
• First performance at the Teatro Dal Verme, Milan, on 21st May 1892.

Tonio appears in the prologue, followed by the first act, in which the people of a Calabrian village celebrate the Feast of the Assumption and the arrival of the players. Canio, dressed, as are the other players, in the costumes of the play they will act, tells the people the story they will show, how Pagliaccio will take jealous revenge on the clown, his wife's lover. Canio shows jealousy of Nedda, resenting Tonio's attentions to her. Canio and Beppe leave, and Tonio now makes advances to Nedda. She seizes a whip and strikes him, to his anger. He threatens revenge. Silvio now calls to Nedda and reminds her of her promise to elope with him after the play. Tonio overhears them and brings Canio back, but Silvio has made his escape. Nedda refuses to tell her husband the name of her lover, but he is prepared to wait. Canio now makes ready for the play, although his feelings, which he must hide, are in turmoil. The second act finds the play about to start. Tonio bangs the drum, Nedda goes among the audience collecting money and takes the opportunity to warn Silvio. In the play Nedda, as Columbine, awaits her lover Harlequin, who serenades her. The clown Taddeo returns from the market, makes advances to Columbine and is decisively rejected, turned out of the room by Harlequin, who has now made his appearance. Taddeo brings news of Pagliaccio’s imminent return, and Harlequin makes his escape, reminding Columbine to use drugged wine he has brought to put her husband to sleep. Canio's jealousy takes over, as he seeks to force Nedda to reveal the name of her lover. The audience is now alarmed, since it is clear that Canio is no longer acting and that Nedda is terrified for her life. She tries to escape him, but he stabs her in the back and kills Silvio, who has leaped up, trying to intervene.

Leoncavallo based his realistic opera on an incident in the Calabrian village of Montalto, where the subsequent trial had been before his father as magistrate. Often given in a double bill with Mascagni's verismo opera Cavalleria rusticana (Rustic Chivalry), another story of love and jealousy, Pagliacci remains one of the best known operas in the repertory. Tonio's Prologue serves at times as a dramatic concert piece, outdone in popularity only by Canio's moving and dramatic Vesti la giubba (On with the motley), before the play, followed by an instrumental Intermezzo. Harlequin's serenade O Columbina offers an element of irony, while Canio's No, Pagliaccio non son (No, I am not Pagliaccio) brings the drama to its climax.