Jan z Jenštejna, German: Johann II. von Jenstein, Johannes VI. von Jenstein. Johann von Jenzenstein, Johann von Genzenstein (1348, Prague, Royal Bohemia, Lands of the Bohemian Crown – 17 June, 1400, Rome) was the Archbishop of Prague 1379–1396. He studied in Bologna, Padova, Montpellier and Paris. He was also poet, writer and composer.
In 1379 he became the owner of the castle Hrádek. In 1379 he succeeded to the archbishopric of his uncle Jan Očko z Vlašimi who had stepped down. Soon he became Chancellor to Wenceslaus IV of Bohemia. The next year the capital was struck by a Plaque epidemic, which struck him as well. He recovered, but this episode left deep scars on his character and he began to examine theological and philosophical problems at his castle Helfenburk u Úštěka. He had abandoned public life because of a quarrel with Wenceslav IV, which was mainly over the matter of the Popes of Avignon. Jan was still loyal to Pope Urban VI, to whom the king was not. In 1384 he left his chancellor post. The quarrel with the king removed him completely from political life, and he retired to his castle and abandoned the post of archbishop on 2 July 1396. He was succeeded as archbishop by Olbram ze Škvorce.
While on his castle, he fell from a newly built tower and miracurously managed to grab hold of something before falling to the ground. He died in Rome in 1400, and all his possessions, including his castle, passed to the Archbishops of Prague.