Janusz z Tarnowa was Archbishop of Gniezno, Poland.

[2] Brave, educated and well versed in political matters, he skilfully ruled the Archdiocese in the troubled and difficult times of the second invasion of the Tatars, and the Lithuanian pillaging of Mazowsze.

Jan Długosz maintains that he was from Grzymałów, but this remains un-established, as is the hypotheses he belonged to the Knights of Tarnawów's.

[4] A trusted official and collaborator for 20 years, of Pełka, he was unanimously supported as his replacement and was appointed archbishop on 20 May 1258.

One of the most momentous events of his tenure was the canonization in 1266 of Jadwiga Śląska by Pope Urban IV and as Archbishop he convened several provincial councils.