The Diocese of Saint Thomas in the Virgin Islands (Latin: Diœcesis Sancti Thomae in Insulis Virgineis) is a Latin Church ecclesiastical territory or diocese of the Catholic Church for the U.S. Virgin Islands. It is the only suffragan diocese in the ecclesiastical province of the metropolitan Archdiocese of Washington.
The mother church of the diocese is Saints Peter and Paul Cathedral in St. Thomas. The bishop of St. Thomas belongs to the United States Conference of Catholic Bishops and is an observer with the Antilles Episcopal Conference. Since 2021, the Bishop of St. Thomas has been Jerome Feudjio.