The notion of law (Gesetz) plays a number of highly visible systematic roles within Kant’s critical philosophy. Perhaps the most famous instance of law is found in Kant’s practical philosophy, where it finds expression in the idea of the moral law, which takes the form of a Categorical Imperative for finite autonomous agents such as ourselves. But the notion of law is foundational in his theoretical philosophy as well, in the form of the notion of a law of nature, which was central to the views of many leading proponents of the Scientific Revolution (esp. Descartes and Newton). Despite the fact that Kant divides philosophy into a metaphysics of morals and a metaphysics of nature, it would be a mistake to think that Kant envisions a place in his philosophy for only two laws: one that would be constitutive of the metaphysics of morals (the moral law) and a second that would underlie the metaphysics of nature (a law of nature). For Kant also accepts numerous other laws that have a different status and play different roles within his philosophy as a whole. For example, Kant is committed not only to highly abstract laws of nature such as the Second Analogy’s causal principle, but also to the existence of various empirical laws in the different sciences, including the law of universal gravitation as well as both mechanical (5:387) and teleological laws (5:409). He also emphasizes several higher-level laws, such as the laws of genera (A653/681), specification (A656/B684), and continuity (A660/B688), which serve as regulative principles. In addition, Kant foresees what are best characterized as laws of rational cosmology stating that there can be no leap, no gap, no fate, and no chance in the world (A228/B280). In fact, even more fundamentally, Kant is committed to laws that obtain for the intelligible world and to the idea that such laws both reveal themselves as imperatives to us and ground the laws of the sensible world (4:453-454). Despite this diversity of ways in which Kant deploys laws within his philosophy, in each case the law shares a core content and a fundamental presupposition. The core content is that a law must be in some sense necessary and thus established by some kind of act of legislation. The fundamental presupposition is that the law must, in every case, be actively legislated by a faculty that has the authority to undertake this act. In this paper I argue that Kant is surprisingly flexible and creative in ascribing the legislation of laws to different aspects of our spontaneous intellectual faculties, while still holding on to the core content and presupposition of law. Thus, the laws of nature derive from the understanding, aided, in the case of empirical laws, by the reflective power of judgment, while the moral law derives from the demands of reason. Several of the higher-level regulative principles derive from reason just as the moral law does, but Kant holds that they depend on reason’s desires or needs, which gives them an interestingly different status from that of either the moral law or the laws of nature.