Johannes Trithemius (; 1 February 1462 – 13 December 1516), born Johann Heidenberg, was a German Benedictine abbot and a polymath who was active in the German Renaissance as a lexicographer, chronicler, cryptographer, and occultist.
He had considerable influence on the development of early modern and modern occultism.
His students included Heinrich Cornelius Agrippa and Paracelsus.