Giuseppe Jannacconi (11/01/1740 - 16/03/1816), an Italian composer, one of the last in the style of Palestrina. Jannaconi was born in Rome, and studied under S. Rinaldini and Giuseppe Carpani. He is known for scoring many of Palestrina's works, aided by his friend Pasquale Pisari, as well as composing many of pieces of church music himself. Among other positions, towards the end of his life in 1811 he succeeded Niccolò Antonio Zingarelli as maestro di cappella at St. Peter's Basilica. He died in Rome.

According to Fétis he studied music first with Don Soccorso Rinaldini, a papal singer, then with Gaetano Carpani, the teacher of Clementi, who was a fellow student. The formative influence on him was Pasquale Pisari, whose assistant he later became. Pisari introduced him to the strict counterpoint of the Roman school and gave him his own research notes, from which Jannacconi acquired a close familiarity with the Palestrina style. He passed on his knowledge and his notes to Giuseppe Baini, his pupil (from 1802) and friend, who made use of them in his celebrated study of Palestrina, published in 1828. In 1779 Jannacconi applied for the post of maestro di cappella at Milan Cathedral, but was not able to go there for the competition and Giuseppe Sarti was given the position. He became a music teacher in the orphanage at Rome; from 1811 until his death he was maestro di cappella at S Pietro, succeeding N.A. Zingarelli. Jannacconi was one of the last representatives of the Roman school. Even when he employed instrumental accompaniment, his music, which may be in as many as 16 parts, adheres to the principles of the stile osservato or the stile concertato. His importance for the 18th-century ‘Palestrina style’ lies less in his works than in the fact that his study of the stile antico was based on Palestrina's actual music, thus making a substantial contribution towards a better understanding of the style. Abbé Santini, another of Jannacconi's pupils, was a keen collector of his music, and many of Jannacconi's works are now preserved in the Santini collection in Münster.