The Diocese of Boac is a Roman Catholic diocese located in the Philippines, specifically on the island of Marinduque. Established in 1977, it serves as a spiritual and administrative region for the Catholic Church, overseeing various parishes and communities within its jurisdiction. The diocese is part of the ecclesiastical province of Manila. The seat of the diocese is the Cathedral of St. Joseph the Worker in Boac, the capital of Marinduque. The diocese focuses on promoting the Catholic faith, providing pastoral care, and engaging in community development initiatives. It plays a vital role in the religious and cultural life of the local population.