Massa Marittima Cathedral (Italian: Duomo di Massa Marittima; Cattedrale di San Cerbone) is a Roman Catholic cathedral in Massa Marittima, Tuscany, Italy, dedicated to Saint Cerbonius. Formerly the episcopal seat of the Diocese of Massa Marittima, it is now that of the Diocese of Massa Marittima-Piombino.
The cathedral measures 58.72 metres (192.7 ft) by 18 metres (59 ft) and is built on the ground plan of a Latin cross.
The façade reveals the different influences which inspired the anonymous architect: the blind arcades in the lower part, decorated with circular openings and lozenges, the loggiato in the middle part and the surmounting tympanum are in Pisan Romanesque style. The large ogival mullioned window and the three spires show instead a Sienese influence.
The central portal flanked by two lion columns has five panels dating from the early 13th century illustrating the legend of Saint Cerbonius. The three central columns of the tympanum rest on three figures: a bearded man, a griffin and a horse.
The bell tower is the original 13th-century one in the lower part while the upper area is a 19th-century addition. The polygonal tambour, standing at 37.86 metres (124.2 ft), is from the 15th century.