ACF Fiorentina, commonly referred to as Fiorentina (pronounced [fjorenˈtiːna]), is an Italian professional football club based in Florence, Tuscany. The original team was founded by a merger in August 1926, while the current club was refounded in August 2002 following bankruptcy. Fiorentina have played at the top level of Italian football for the majority of their existence; only four clubs have played in more Serie A seasons.

Fiorentina has won two Italian league titles, in 1955–56 and again in 1968–69, as well as six Coppa Italia trophies and one Supercoppa Italiana. On the European stage, Fiorentina won the UEFA Cup Winners' Cup in 1960–61. They also lost five finals, finishing runners-up in the 1956–57 European Cup (the first Italian team to reach the final in the top continental competition), the 1961–62 Cup Winners' Cup, the 1989–90 UEFA Cup, and in the 2022–23 and 2023–24 editions of the UEFA Conference League, being the first club to record two consecutive final appearances and two consecutive defeats in the competition's history.

Fiorentina is one of fifteen European teams that have played in the finals of all three major continental competitions (the European Cup/Champions League, the UEFA Cup Winners' Cup and the UEFA Cup/Europa League) and in 2023, by reaching the Europa Conference League final, Fiorentina became the first team to reach all four major European club competition finals (excluding the one-off match of the UEFA Super Cup).

Since 1931, the club have played at the Stadio Artemio Franchi, which currently has a capacity of 43,147. The stadium has used several names over the years and has undergone several renovations. Fiorentina are known widely by the nickname Viola, a reference to their distinctive purple colours.