| Jurisdiction: | Diocese |
| Jeju | |
| Latin: | Dioecesis Cheiuensis |
| Local: | 제주교구 |
| Territory: | Jeju Province |
| Province: | Gwangju |
| Metropolitan: | Gwangju |
| Area Km2: | 1,848 |
| Population: | 678,772 |
| Population As Of: | 2017 |
| Catholics: | 81,411 |
| Catholics Percent: | 12.1 |
| Parishes: | 28 |
| Denomination: | Catholic |
| Sui Iuris Church: | Latin Church |
| Rite: | Roman Rite |
| Established: | 28 June 1971 (years ago) |
| Cathedral: | Immaculate Conception Cathedral, Jeju City |
| Bishop: | Pius Moon Chang-woo |
| Bishop Title: | Bishop |
| Metro Archbishop: | Hyginus Kim Hee-jong |
| Emeritus Bishops: | Paul Kim Tchang-ryeol Peter Kang U-il |
| Map: | Diocese of Jeju.svg |
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).[1]
As per 2014, it pastorally served 71,845 Catholics (11.9% of 604,670 total) on 1,849 km2 in 27 parishes with 51 priests (44 diocesan, 7 religious), 1 deacon, 110 lay religious (7 brothers, 103 sisters) and 17 seminarians.