Carrozzeria Castagna is an Italian coachbuilding company based in Milan, Italy.

A coachbuilder or body-maker is a person or company who manufactures bodies for passenger-carrying vehicles. Coachwork is the body of an automobile, bus, horse-drawn carriage, or railway carriage. The word "coach" was derived from the Hungarian town of Kocs. A vehicle body constructed by a coachbuilder may be called a "coachbuilt body" or "custom body".