The Roman Catholic Diocese of San José in California (; ) is an ecclesiastical territory or diocese of the Roman Catholic Church in the northern California region of the United States. It comprises Santa Clara County, and is led by a bishop. Its patron saints are Saint Joseph and Saint Clare of Assisi. The diocese is a suffragan of the Archdiocese of San Francisco. Its fellow suffragans include the Dioceses of Honolulu, Las Vegas, Oakland, Reno, Sacramento, Salt Lake City, Santa Rosa and Stockton.