János Szily (20 August 1735, Felsőszopor - 2 June 1799, Szombathely) was a Hungarian Catholic bishop and patron of the arts.
After completing his primary and secondary studies at Jesuit schools in Sopron, he embarked on an ecclesiastical career, which led him to the Collegium Germanicum et Hungaricum in Rome, where he was an honor student.
With sketches and plans sent to him by his agents in Rome, he began a series of architectural projects; demolishing the ruins of the old fortifications, building a seminary (1777-1780), Bishop's palace (1780-1783) and a cathedral (1791-1797).
For the execution and decoration of these buildings, he retained the services of several well known architects and artists; including Melchior Hefele [hu], Stephan Dorfmeister, Franz Anton Maulbertsch and Josef Winterhalder.
In addition to founding schools, he donated a large sum to the writer, Miklós Küzmics, who translated the Bible into Prekmurje Slovene, thereby establishing a standard for that dialect.