Jan Firlej (c. 1521, Dąbrowica, Lublin County – 1574, Kock) was a Polish nobleman (szlachcic), and Calvinist activist.

Jan became Crown Grand Marshal in 1563 and starost of Kraków in 1572.

He agreed to the candidature of Henry III of France for the throne of Poland only on the condition that Henry sign the Henrican articles.

He also held the titles of Voivode of Bełz, Lublin, and Kraków.

Around 1555, he founded a Calvinist church in Kock and built a family residence there.