The scene is set in Seville. On an earlier visit to Seville, the young and dashing Count Almaviva saw a beautiful girl whose name, he discovered, is Rosina. Now, as dawn breaks, he has come with a group of musicians to serenade her and to win her heart. The Count hides when Figaro, the barber, bounds in, boasting of his busy life as the neighborhood factotum. Figaro recognizes the Count as a former employer. He tells him that Rosina is kept a virtual prisoner in the house. She is the ward of Doctor Bartolo, who plans to marry her himself. Figaro agrees to help Almaviva win the hand of Rosina. Their conversation is interrupted by Doctor Bartolo. As soon as the Doctor leaves, Almaviva launches into his second serenade. He describes himself as a poor student, Lindoro. Rosina attempts to reply, but retreats when someone enters her room. Figaro suggests that Almaviva disguise himself as a soldier and demand quarters in the house. As the Count dwells on his love, Figaro happily anticipates his reward.

Rosina resolves to oppose Bartolo and to marry the young student, who has touched her heart. Bartolo hears of Almaviva’s interest in his ward from Don Basilio, Rosina’s music teacher. Basilio reports that the Count has been seen in the neighborhood. To drive Almaviva away, he proposes a campaign of slander. However, Bartolo is afraid it will take too long. Figaro, having overheard them, warns Rosina that the Doctor plans to marry her the very next day.

Berta, the maid, answers a violent knocking at the door. It is Almaviva, disguised as a drunken soldier, seeking a night’s lodging. During the ensuing argument with Bartolo, he slips a love note to Rosina. Figaro rushes in to warn that a crowd, attracted by the sounds of the argument, has gathered in the street. Police arrive to quiet the disturbance. Almaviva whispers his identity to the officers, and is immediately released, to the bewilderment of the others.

Pleased to be rid of Almaviva, Bartolo finds himself greeted by a young music teacher, “Don Alonzo”. The Count has taken another disguise and claims to be a substitute for Basilio. Rosina, recognizing her suitor, begins her music lesson as Bartolo dozes in his chair. Figaro appears to shave the Doctor. But Basilio’s arrival creates a problem. The real music teacher, bribed by Almaviva, feigns illness and departs. Figaro keeps Bartolo distracted as the Count and Rosina plot a midnight elopement. However, the suspicious Doctor overhears them. He drives the conspirators from the house and sends Rosina to her room.

Later, Bartolo persuades Rosina that Lindoro is a servant of Almaviva, who is plotting her seduction. Shocked, Rosina agrees to marry Bartolo. There is a violent thunderstorm. Almaviva and Figaro climb through a window. Rosina furiously accuses them of betrayal. When Almaviva finally reveals that he is not Lindoro, but the Count himself, they fall into each other’s arms. They are about to leave, only to discover that the ladder has been removed from the window. Basilio arrives with a Notary. Although he has been summoned to marry Rosina and Bartolo, the official is instructed to perform the ceremony for the lovers. Rushing in too late, Bartolo is forced to bestow his blessing on the couple. All join in a final chorus of rejoicing.