Saint Romulus of Fiesole was bishop of Fiesole during the 1st century. He is venerated as the patron saint of Fiesole, Italy. Romulus was probably a local deacon, priest, or bishop of the 1st century.

The Diocese of Fiesole is a Latin diocese of the Catholic Church in Tuscany, central Italy, whose episcopal see is the city of Fiesole. Fiesole was directly subject to the pope until 1420, when the archdiocese of Florence was created and Fiesole was made one of its suffragan bishops. It is still a suffragan of the Metropolitan Archbishopric of Florence.