(June 11, 1289), in Italian history, a battle between Florence and Arezzo, an episode in the struggles among rival Tuscan towns and in the contest between the Guelfs and Ghibellines (Guelf and Ghibelline) (pro-papal and pro-imperial parties in Italy). The battle marked the beginning of the hegemony of the Florentine Guelfs over Tuscany.

Florence, encouraged to fight by Guelf partisans exiled from Arezzo by Ghibellines in 1287, was aided by its allies (Pistoia, Lucca, Bologna) and by a small contingent from Charles II of Naples, leader of the Guelf party in Italy. A cavalry charge decided the battle in favour of Florence. Among the Florentines who fought at Campaldino was the poet Dante.