Francesco Vanni was an Italian painter, draughtsman, printmaker, publisher and printer active in Rome and his native city of Siena.

Vanni was part of a family of painters, including his half-brother Ventura Salimbeni and stepfather Arcangelo Salimbeni, the latter of whom died when Francesco was young. As a 16-year-old, Vanni went first to Bologna, then to Rome. He apprenticed with Giovanni de' Vecchi during 1579–80, also being influenced, like other Tuscan painters of his day, by Federico Barocci from Urbino. Vanni was among the last painters who reflected the influence of the Sienese School of painting. He was named a Cavalieri.

In Rome, he worked later with Salimbeni, Bartolomeo Passerotti, and Andrea Lilio. He was commissioned by Pope Clement VIII to paint an altarpiece for the St. Peter's, later transferred to mosaic, Simon Magus rebuked by St. Peter. He painted several other pictures for Roman churches; including St Michael defeats rebel angels for the sacristy of S. Gregorio; a Pietà for Santa Maria in Vallicella; and the Assumption for San Lorenzo in Miranda.

Returning to Siena, where he ultimately died, he afterwards worked at Parma, Bologna, and again at Rome. At Siena, he painted a S. Raimondo walking on the Sea for the church of the Dominicans. Vanni painted a Baptism of Constantine (1586–87) for the church of San Agostino in Siena. He painted a Christ appearing to St. Catherine for the chapel of il Refugio at the Sanctuary of Santa Caterina di Siena, and a Baptism (1587) for the former church of San Giovannino e Gennaro, Siena. He painted an Immaculate Conception (1588) for the Montalcino Cathedral and an Annunciation (1589) for the church of Santa Maria dei Servi in Siena. He painted a "Crucifixion with Father Matteo Guerra" for San Giorgio.

He was active as a printmaker and etched three devotional prints after his own designs. He was further the publisher of a large 4-plate map of Siena which he had designed himself and had engraved by the Flemish engraver Pieter de Jode the Elder. He applied in 1595 to Lorenzo Usimbardi for help in obtaining financial support in the publication of the map.

His sons, Michelangelo and Raffaello Vanni were also painters. Among his pupils were Astolfo Petrazzi and Rutilio Manetti. The painter from Perugia, Benedetto Bandieri, claimed to be a descendant of Vanni.