The Diocese of Saint Joseph (Latin: Dioecesis Sancti Iosephi) was a Latin Church ecclesiastical territory or diocese of the Roman Catholic Church in the northwestern part of the state of Missouri in the United States, erected on March 3, 1868, with territories taken from the Archdiocese of Saint Louis.

During the Second Plenary Council of Baltimore in 1866, St. Joseph was proposed to become its own diocese.

[1] On September 10, 1800 Bishop Hogan was transferred to the Diocese of Kansas City and Bishop Maurice Francis Burke was moved from the Diocese of Cheyenne, Wyoming to take his place.

[1] As of 1911, the diocese had accumulated 8 parishes, 12 priests, 6 parish schools, a college created by the Christian Brothers, and a school for young women created by the Sisters of Charity.

This article on a Roman Catholic diocese in the United States is a stub.