Jan Očko z Vlašimi (died 1380; Jan VIII as the Bishop of Olomouc), from the family of the House of Vlašim, was the second Archbishop of Prague (1364–1378). He was the uncle to his successor Jan z Jenštejna .
It is not known when he was born. His father was Jan z Kamenice, the secretary of king John of Bohemia. Brothers were Michael z Vlašime, Burgrave of Svojanov, and Pavel z Vlašime a z Jenstejna, Grand Chamberlain.
As of 1351, Jan Očko was the Bishop of Olomouc. His coat-of-arms was that of bishop and silver two Vulture heads gules (common with z Vlasime a z Jenstejna).
At that time, he became an advisor to Charles IV. He later accompanied Charles IV on his way to Italy in 1355. On July 12, 1364, he became the Archbishop of Prague, succeeding the dead Arnošt of Pardubice.
In 1368, he was regent of the Kingdom of Bohemia.
He consecrated the Church of Saint Thomas in Brno (March 13, 1356) and the Emmaus monastery in Prague on March 29, 1372.
In 1366 he ordered the incarceration of Jan Milíč z Kroměříže for his preachings against Charles IV, whom he called the "Antichrist". Jan Milíč was later freed by Charles and remained in his favour.
On September 18, 1378, by nomination of Pope Urban VI, he became the first Bohemian named a Cardinal. On November 30, 1379, he abandoned the post of Archbishop. According to Konrad Eubel, Joannes de Jenzenstein was appointed to succeed him on 19 March 1379.