In this dissertation, I develop a new theory of criminal law that rests on Kantian principles. I show that attention to two aspects of Kant’s political theory—his accounts of civic freedom and civic virtue—can help us develop a more just model of criminal law. In particular, I argue that we may properly criminalize only those activities which, by their nature, violate certain conditions enabling citizens to pursue their civic freedom. I then propose expanding the use of the jury in order to develop civic virtues that citizens of a just society ought to embrace. Finally, I argue that Kantian principles can both show why criminal punishment is necessary, and also help us discern its proper modes and extent.