The Iron Tower is a mediaeval tower dating to the early 13th century, and modified in the 15th century, which with the Wood Tower and the Alexander Tower is one of three remaining towers from the city walls of Mainz, Germany. Its name derives from the Iron Market (Eisenmarkt), which was held in the immediate vicinity until the 19th century.
The Iron Tower served as a watchtower and gate to the city, and later as a gaol. It was badly damaged in World War II and reconstructed in the 1960s. Today it houses various organisations and arts projects and is used for art exhibitions.