Huldrych Zwingli's understanding of original sin is usually sidelined in contemporary Reformed theology. In this paper I argue that Zwingli's views are worthy of theological retrieval for contemporary dogmatics. His position offers a moderate version of the doctrine that has ecumenical promise. It also avoids well-known objections to some later Reformed views such as that it unjustly imputes guilt to the innocent, and the sin of one (Adam) to the many (humanity). Although there are some difficulties in Zwingli's account, I argue that his doctrine provides a useful framework for a contemporary moderate Reformed account of original sin. Huldrych Zwingli's understanding of original sin is usually sidelined in contemporary Reformed theology. In this paper I argue that Zwingli's views are worthy of theological retrieval for contemporary dogmatics. His position offers a moderate version of the doctrine that has ecumenical promise. It also avoids well-known objections to some later Reformed views such as that it unjustly imputes guilt to the innocent, and the sin of one (Adam) to the many (humanity). Although there are some difficulties in Zwingli's account, I argue that his doctrine provides a useful framework for a contemporary moderate Reformed account of original sin.