Felix Manz (also Felix Mantz) (c. 1498 – 5 January 1527) was a co-founder of the original Swiss Brethren Anabaptist congregation in Zürich, Switzerland, and the first martyr of the Radical Reformation.
Manz was born and died in Zürich, where his father was a canon of Grossmünster church. Though records of his education are scant, there is evidence that he had a liberal education, with a thorough knowledge of Hebrew, Greek and Latin. Manz became a follower of Huldrych Zwingli after he came to Zürich in 1519. When Conrad Grebel joined the group in 1521, he and Manz became friends. They questioned the mass, the nature of church and state connections, and infant baptism. After the Second Disputation of Zürich in 1523, they became dissatisfied, believing that Zwingli's plans for reform had been compromised with the city council.
Grebel, Manz and others made several attempts to plead their position. Several parents refused to have their children baptized. A public disputation was held with Zwingli on 17 January 1525. The council declared Zwingli the victor.
After the final rebuff by the city council on 18 January, in which they were ordered to desist from arguing and submit to the decision of the council, and have their children baptized within eight days, the brethren gathered at the home of Felix Manz and his mother on 21 January. Conrad Grebel baptized George Blaurock, and Blaurock in turn baptized the others. This made complete the break with Zwingli and the council, and formed the first church of the Radical Reformation. The movement spread rapidly, and Manz was very active in it. He used his language skills to translate his texts into the language of the people, and worked enthusiastically as an evangelist. Manz was arrested on a number of occasions between 1525 and 1527. While he was preaching with George Blaurock in the Grüningen region, they were taken by surprise, arrested and imprisoned in Zürich at the Wellenburg prison.