The Diocese of Bà Rịa (Latin: Dioecesis Barianensis) is a Latin rite suffragan diocese in the ecclesiastical province of the Metropolitan Archdiocese of Saigon, in southern Vietnam, yet it depends on the missionary Dicastery for Evangelization.

Its cathedral episcopal see is Cathedral of Mary, Mother of God, dedicated to the Apostles Saint Philip and Saint James, in the city of Bà Rịa, Bà Rịa–Vũng Tàu province, Southeastern Vietnam.

The bishopric was established on 22 November 2005 as Diocese of Ba Ria / Bà Rịa (Tiếng Việt) / 巴地 (正體中文) / Barianen(sis) (Latin adjective), on territory detached from the Diocese of Xuân Lôc.

[2] According to Jesuit missionaries, in 1670, in Xích Lam (Ðất Ðỏ), near Bà Rịa, there were nearly 300 Catholic families.

),[7] R. Moxoai (Mô Xoài), Ba-ria (Bà Rịa), Nui-nua (Núi Nứa) and Ðất Ðỏ, under the care of MEP and Jesuit missionaries.