The Metropolitan Archdiocese of Seoul (Latin: Archidioecesis Metropolitae Seulensis, Korean: 서울대교구) is a Metropolitan archdiocese of the Latin Church of the Catholic Church comprising the metropolitan area of Seoul, South Korea, whose province comprises parts of South Korea (which has two more provinces) and all North Korea, yet depends on the missionary Dicastery for Evangelization.

Pope Francis announced that the Archdiocese will be the host of the 2027 international celebration of World Youth Day.

[1] Pope Leo XIII was the first to approve the separation of the community from the control of diocese of Beijing and assigned priests from the Paris Foreign Missions Society but never went due to the Anti-Christian sentiment and persecutions during that time.

Pope Gregory XVI issued a papal bull, Ex debito pastoralis, on 9 September 1831, establishing the Apostolic Vicariate of the Korean Kingdom, 조선/Corea (Curiate Italian)/朝鮮 (正體中文), on territory split off from the then Diocese of Peking,[3] in what used to be part of Imperial China.

The Metropolitan's ecclesiastical province comprises his own Archdiocese and the following suffragan bishoprics, mostly in South Korea :