John Thomas Steinbock (July 16, 1937 – December 5, 2010) was an American prelate of the Roman Catholic Church. He served as the fourth bishop of the Diocese of Fresno in California from 1991 until his death in 2010. Steinbock previously served as an auxiliary bishop of the Diocese of Orange in California from 1984 to 1987 and as bishop of the Diocese of Santa Rosa in California from 1987 to 1991.