The Reformation in Zürich was promoted initially by Huldrych Zwingli, who gained the support of the magistrates of the city of Zürich and the princess abbess Katharina von Zimmern of the Fraumünster Abbey, and the population of the city of Zürich and agriculture-oriented population of the present Canton of Zürich in the early 1520s. It led to significant changes in civil life and state matters in Zürich and spread to several other cantons of the Old Swiss Confederacy, and thus initiated the Reformation in Switzerland.

Katharina von Zimmern, also known as the imperial abbess of Zürich and Katharina von Reischach, was the last abbess of the Fraumünster Abbey in Zürich.