Torre del Gallo, Medieval tower in Arcetri hills, Florence, Italy.

Torre del Gallo is a 12th-century castle on the Arcetri ridge at Pian de' Giullari, dominated by a raised, crenellated tower. Its fifteenth-century courtyard has three sides of Corinthian columns and round arches, attributed to Brunelleschi; a second neo-Gothic courtyard displays coats of arms added by Stefano Bardini. The marble loggia echoes Jacopo Sansovino's Venetian style.

The tower was partially destroyed in 1280 during conflicts between Guelphs and Ghibellines and later suffered damage from John Hawkwood's raids in 1364. It served as a military command post during the siege of Florence in 1529.

In 1872 Count Paolo Galletti installed a small museum to Galileo here, with busts, portraits and relics, and had Gaetano Bianchi fresco the rooms. Most of the pieces later went to the Museo Galileo in Piazza dei Giudici. A plaque records that Bardini's works were to be finished in 1907.

The complex stands on a ridge at Pian de' Giullari, in the Arcetri hills above Florence, and is privately owned, so the interiors and courtyards are not open to visitors. The tower and its neo-medieval additions can be seen from the surrounding lanes and footpaths, which climb steeply from the city. A plaque on the building records the completion of Bardini's works in 1907.

During the 1529-1530 siege of Florence, Pier Maria III de' Rossi, Count of San Secondo and commander of the Imperial troops, was hosted here by Bartolomeo Lanfredini. From the top of the tower the artillery fire was directed against Michelangelo's fortifications at San Miniato al Monte, with the guns placed near Villa Giovannelli.