Ivan Buchko or Bučko (Ukrainian: Іван Бучко; 1 October 1891 – 21 September 1974) was a Ukrainian Greek Catholic hierarch in present-day Ukraine, United States and Italy. He was the auxiliary bishop of the Ukrainian Catholic Archeparchy of Lviv from 1929 to 1940, the auxiliary bishop of the Apostolic Exarchat in the United States for the Ukrainians from 1940 to 1945 and the first Apostolic Visitator for the Ukrainians in the Western Europe from 1945 to 1971. From 20 October 1929 as titular bishop of Cadi and from 27 April 1953 as titular archbishop of Leucas.