Torre di Castiglioncello, 16th century defensive tower in Castiglioncello, Italy

The Torre di Castiglioncello is a square-plan watchtower of the mid-16th century in Rosignano Marittimo, standing beside the Oratorio di Sant'Andrea Apostolo. Its massive body has few large openings and rests on a battered retaining wall, with the entrance above it. Two floors with very thick walls lie inside; the roof lost the gallery that once ran over pointed arches on perimeter corbels.

The Medici family built this stone tower during the 1500s to defend the coast against pirate raids and naval invasions from foreign powers. The tower formed part of a broader coastal defense system that protected the Tuscan shoreline from repeated threats.

The tower's name comes from the Castiglioncello hamlet, and it stands beside the Oratorio di Sant'Andrea Apostolo. In the 19th century it passed to Diego Martelli, a patron and friend of the Macchiaioli painters, who gathered at his nearby estate; the tower later became part of Count Gualtiero Danieli's neo-medieval villa.

The tower stands next to the Oratorio di Sant'Andrea Apostolo in Castiglioncello, in the municipality of Rosignano Marittimo. A restoration completed in December 2002 returned the structure to its original condition and improved access to it. Inside, two usable floors are separated by very thick walls.

An inscription over the entrance door records that the tower was built by Cosimo II de' Medici, though the structure is not listed among fortifications of 1539, suggesting construction after 1540 and completion by 1570. The roof once carried a gallery over pointed arches on corbels, later replaced by battlements that have since disappeared.