The Diocese of Daejeon (, Hangul: ) is a Latin Catholic diocese of the Catholic Church in South Korea. It is the diocese for Daejeon, South Korea. Augustinus Kim Jong-soo has been appointed its bishop; Stephanus Han Jung-hyun is auxiliary bishop.
On 23 June 1958 Pope Pius XII erected the apostolic vicariate of Daejeon. The vicariate was made a diocese on 10 March 1962 by Pope John XXIII.