Jan Jansz de Bakker van Woerden (Latin name: Johannes Pistorius Woerdensis; 1499 – 15 September 1525) was a Roman Catholic priest who was the first preacher in the Northern Netherlands to be put to death as a direct result of his Protestant beliefs.
Jan de Bakker's father was a sexton in Woerden and also tenant of the brickworks, and his surname may have been derived from that profession. Bakker was a pupil of Johannes Rhodius (Hinne Rode), headmaster of St. Jerome School of the Brethren of the Common Life in Utrecht, who was a proponent of Sacramentarianism. The Dutch Sacramentarians rejected the sacraments of the Catholic Church and denied that the host consecrated at Mass was the real body and blood of Jesus Christ. They called indulgences and pilgrimages mere idolatry and were critical of the low moral standards and conduct of the clergy. In 1520 Bakker's father called him back to Woerden, concerned that some of his views were contrary to the Church's doctrine and could get him in trouble with the authorities. Bakker transferred to the Catholic University in Leuven and in 1522 completed his education there.