The Roman Catholic Diocese of Jeju (제주, also romanized Jeju, Latin: Dioecesis Cheiuensis) is a Latin rite suffragan diocese in the ecclesiastical province of the Metropolitan Archdiocese of Gwangju, South Korea, yet depends on the missionary Dicastery for Evangelization.

Its episcopal see and mother church is Immaculate Conception Cathedral in Jeju City.

It was created on 28 June 1971 by Pope Paul VI as Apostolic Prefecture of Jeju 제주 / Cheju / 濟州 (正體中文) / Cheiuen(sis) (Latin), exempt, on territory split off from the Archdiocese of Gwangju.

It was elevated on 21 March 1977, also by Pope Paul VI to Diocese of Jeju 제주 / Cheju / 濟州 (正體中文) / Cheiuen(sis) (Latin).

This article on a Roman Catholic diocese in Asia is a stub.