While preparing for their wedding, the valet Figaro learns from the maid Susanna that their philandering master, Count Almaviva, has designs on her. At this, the servant vows to outwit his master. Before long Dr. Bartolo enters with the palace housekeeper, Marcellina, who wants Figaro to marry her to cancel a loan he cannot repay. Marcellina and Susanna trade insults until the amorous page Cherubino arrives, reveling in his infatuation with all women. The Count enters, furious at having caught Cherubino flirting with the gardener’s daughter Barbarina, and the page hides not a moment too soon. The Count pursues Susanna and conceals himself when the gossiping music master Don Basilio approaches, only to reemerge when Basilio mentions Cherubino’s infatuation with the Countess. Almaviva becomes livid when he finally discovers Cherubino hiding in the room. Figaro returns with fellow servants praising the Count’s progressive reform in abolishing the droit du seigneur—the right of a noble to take a manservant’s place on his wedding night. Almaviva banishes Cherubino to serve in his regiment in Seville and leaves Figaro to cheer up the distraught adolescent.
The Countess laments her husband’s waning love but plots to chasten him, with help from Figaro and Susanna. They will send Cherubino, disguised as Susanna, to a romantic tryst with the Count. Cherubino, smitten with the Countess, appears and the two women begin to dress the page for his rendezvous. While Susanna goes out to find a ribbon, the Count knocks on the door, furious to find it locked. Cherubino quickly locks himself in the closet, and the Countess admits her husband, who hears a noise coming from the closet and doubts the Countess’s claim that Susanna is inside the closet. He takes his wife to fetch some tools with which to force open the closet door. Meanwhile, Susanna, having observed everything from behind a screen, hurries Cherubino out a window and takes his place in the closet. Both Count and Countess are amazed to find her there upon their return. All seems well until the gardener, Antonio, storms in with crushed geraniums from a flower bed below the window. Figaro, who has run in to announce that the wedding is ready, contends it was he who jumped from the window and feigns a sprained ankle. Marcellina, Bartolo, and Basilio burst into the room waving a court summons for Figaro, which delights the Count since this gives him an excuse to delay the wedding.
Susanna, encouraged by the Countess, leads the Count on with promises of a rendezvous in the garden. The nobleman, however, grows doubtful when he spies her conspiring with Figaro. As everyone assembles for Figaro’s trial, Barbarina takes Cherubino off to her house where she dresses him as a girl in order to hide from the Count. After the trial is over, the enraged Figaro finds himself sentenced to marry Marcellina—unless he pays her at once. They soon discover, however, that Figaro is actually the offspring of an illicit union between Dr. Bartolo and Marcellina herself. Susanna meanwhile has secured from the Countess enough money to pay off Figaro’s debt and returns to find him embracing the despised housekeeper. The confusion is rapidly cleared, and the couples plan a double wedding, much to the Count’s irritation. The Countess and Susanna resume their plotting, summoning the Count to the garden that evening with a secret letter. They seal it with a pin which the Count is to return to Susanna. A group of village girls, including Barbarina and the disguised Cherubino, arrive to bring flowers to the Countess. Antonio unmasks Cherubino, but Barbarina’s allegations against the flirtatious Count earn them permission to stay at the wedding. Marcellina and Bartolo are married along with Figaro and Susanna, who slips the Count her note.
In the moonlit garden, Barbarina searches for the hatpin the Count asked her to bring to Susanna, which she has dropped, and unwittingly reveals the arrangement to Figaro and Marcellina. Figaro immediately suspects that Susanna is deceiving him and hides to oversee the rendezvous. Susanna and the Countess, who have exchanged clothes in order to deceive the Count, arrive with Marcellina who has warned them of Figaro’s suspicions. Punishing her doubting husband, Susanna torments Figaro with her supposed joy at waiting for the Count. Susanna hides in time to see Cherubino flirting with the Countess disguised as Susanna. The Count soon chases the page away so that he can fulfill his own desires with the supposed Susanna when he is frightened off by Figaro. Figaro attempts to enlist the aid of the supposed Countess, but he needs only a moment to understand from her voice that it is in reality Susanna. He woos her as if she were the Countess in playful revenge, but has only enough time to calm Susanna before the Count returns. Figaro and Susanna, whom the Count takes to be his wife, play an exaggerated love scene for his benefit. Believing the Countess has deceived him, the Count furiously calls everyone to witness her disgrace. He adamantly refuses all pleas for pardon, until the real Countess appears. Grasping the truth at last, the Count begs his wife’s forgiveness.