Hans von Baysen or Jan Bażyński (c. 1394 – 1459) was a Prussian knight and statesman, leader of the Prussian Confederation and the first Polish governor of Royal Prussia.
The Baysen family was part of a larger Flemish family which came in the 13th century from Lübeck or its vicinity. They named themselves after their possession, Basien (modern Bażyny) near Wormditt (modern Orneta) in Ermland (modern Warmia).
Initially, he was employed by the Teutonic Knights and their Grand Masters, among them Konrad von Erlichshausen and Ludwig von Erlichshausen. He was one of the order's native lay associates.
In service of the Grand Masters, Jan traveled on diplomatic missions to England, Denmark and Portugal in the years 1419–1422. According to legend he was knighted by the King of Portugal for his military service against the Moors during the Reconquista, which was reflected in a modification to his family's Coat of Arms. After Michael Küchmeister resigned as head of the order, Bażyński also terminated his service with the knights. He was also one of the ambassadors of Grandmaster Paul von Rusdorf, who appointed him to a member of a secret council.