The Roman Catholic Diocese of St. Catharines is a diocese located in the province of Ontario, Canada. Established in 1956, it serves the spiritual needs of Catholics in the Niagara Peninsula region. The diocese is part of the larger ecclesiastical province of Toronto and is responsible for overseeing various parishes, schools, and community services. The diocese is led by a bishop, who provides guidance and support to the clergy and laity. It focuses on promoting the teachings of the Roman Catholic Church and fostering a sense of community among its members through various programs and initiatives.