John Zápolya or Szapolyai (Hungarian: Szapolyai/ Zápolya János; Croatian: Ivan Zapolja; Romanian: Ioan Zápolya; Slovak: Ján Zápoľský; 1487 – 22 July 1540), was King of Hungary (as John I) from 1526 to 1540. His rule was disputed by Archduke Ferdinand I, who also claimed the title King of Hungary. He was Voivode of Transylvania before his coronation, from 1510 to 1526.
John came from a prominent Croatian-Slavonian noble family. His father became one of Hungary's wealthiest lords and served as Palatine of Hungary.