Clementi was born in Rome on January 23, 1752. He was the eldest child of Nicolo Clementi, a silversmith, and Magdalena Kaiser. Clementi began to learn music from Antonio Baroni (1738-1792), who was a relative. Baroni was in charge of the choir at St. Peter's Basilica. He also had lessons from the organist, Cordicelli, Giuseppe Santarelli (1710-1790) and Gaetano Carpani.