The Roman Catholic Diocese of Tuticorin (Latin: Tuticoren(sis)) is a unit (or 'particular Church') of the Catholic Church in the city of Tuticorin, part of the ecclesiastical province of Madurai in India.

The Catholics of this area trace their origin to the time of St. Francis Xavier who spent most of his missionary life in this area.

Separated from the diocese of Tiruchirapalli, Tuticorin was created as a diocese and entrusted to the diocesan clergy in 1923 by the Apostolic Brief "Quae Catholico Nomini" of Pope Pius XI.

He was also the first Indian bishop of the Latin Rite.

The patrons of the diocese are St. Francis Xavier and St. Teresa of the Child Jesus.