A piazza in Seville, in front of Bartolo’s house. Count Almaviva, grandee of Spain, has seen a beautiful girl on the Prado in Madrid and has followed her to Seville in the disguise of a student. After serenading the girl below her window, he meets by chance his former valet Figaro in front of her house, and learns the girl is the ward of grumpy old Doctor Bartolo. Almaviva enlists Figaro’s help — for a handsome fee, of course — in freeing the lovely and spirited Rosina from her cage. He sings under her window, telling her he is the poor student Lindoro. The ever-inventive Figaro suggests sending the Count into the household disguised as a drunken soldier.

Rosina is determined to meet and conquer her suitor, despite Bartolo’s controlling ways and his equal determination to marry her expeditiously. When Figaro convinces her that she is indeed the beloved of his poor cousin “Lindoro,” she gives Figaro a letter to take to the boy. Meanwhile, Don Basilio, the music teacher, gets wind of the arrival of Count Almaviva in Seville, and warns Bartolo that they must spread some evil rumor about the Count to drive him away lest he come courting Rosina.

The Count comes courting indeed disguised as a soldier, demanding lodging and letting the astonished Rosina know with a wink that he’s beneath the military disguise. Bartolo refuses to billet him. The “soldier” becomes enraged. The police arrive to arrest him, but Almaviva secretly shows them proof of his identity and he is released, to the amazement of all.

Inside Bartolo’s house. Bartolo is lost in thought, “Might the soldier have been a spy?” A visitor enters and introduces himself as “Don Alonso” (Almaviva in disguised), arriving to give the girl a music lesson in place of Don Basilio, who he says is ill. Alonso gains Bartolo’s confidence by showing him Rosina’s letter to “Lindoro,” and offering to tell her that a mistress of Lindoro’s gave it to him, as a way to dissuade Rosina from her crush. Rosina comes out reluctantly, but again recognizing “Lindoro” beneath the disguise, is suddenly delighted to sing for the visiting teacher.

Figaro enters, ready to shave and trim Bartolo and contriving to get a key to Rosina’s balcony. But who should then appear but Don Basilio, in perfect health. Almaviva hastens the course of his illness with a quick bribe, and the others shoo him out. Almaviva whispers to Rosina that he and Figaro will come at midnight to whisk her away to wedded bliss. Bartolo overhears and, realizing he’s been tricked again, chases them all out in a fury.

Later, Bartolo shows Rosina her own note to “Lindoro,” telling her the Count is merely toying with her. Rosina, thunderstruck, discloses the escape plan and agrees to marry Bartolo after all. At midnight, during a thunderstorm, Figaro and the Count arrive for the elopement, and a livid Rosina confronts them. It’s Lindoro she wanted, nothing to do with “your vile Count Almaviva.” The “vile” one reveals himself, and the three are overjoyed — but their joy turns to panic when Figaro realizes the ladder by which they entered has been moved. The doctor has foiled their escape.

A notary enters, followed by Basilio, who after another friendly financial inducement from the Count, agrees to serve as wedding witness. By the time Bartolo rushes back in, the deed is done, the girl has become a Countess and the dowry is the doctor’s to keep.

Love has triumphed and everyone’s good spirits are restored.