The Diocese of Tainan () is a Latin Church diocese of the Catholic Church in Taiwan.
Erected in March 1961 from territories belonging to the former Apostolic Prefecture of Kiayi, the diocese is a suffragan of the Archdiocese of Taipei.
Ordinaries
Stanislaus Lo Kuang (21 March 1961 Appointed – 15 February 1966 Appointed, Archbishop of Taipei) Paul Ch'eng Shih-kuang (7 June 1966 Appointed – 3 December 1990 Retired) Joseph Cheng Tsai-fa (3 December 1990 Appointed – 24 January 2004 Appointed, Archbishop of Taipei) Bosco Lin Chi-nan (24 January 2004 Appointed – 14 November 2020 Retired) John Lee Juo-wang (14 November 2020 Appointed – 19 June 2021 Resigned) Bosco Lin Chi-nan (Apostolic Administrator) (19 June 2021 Appointed) John Baptist Huang Min-Cheng, O.F.M. (3 May 2023 Appointed)