Jan Łaski or Johannes Alasco (1499-1560) was a cleric, whose uncle, the eponymous Jan Łaski (1456-1531) was Grand Chancellor of the Crown, Archbishop of Gniezno and Primate of Poland. His nephew was an early convert to Calvinism and had a hand in implementing (c. 1543–1555) Reformation in England where he is known as John Laski.