Given the paradoxical implications often associated with Kant’s conception of moral autonomy, an important question to ask, for the purpose of understanding its emergence, is the following: Why might Kant have considered the political notion of autonomy apt for expressing the principle of morality? To answer this question, I start from Kant’s claim that the Formula of Autonomy – in the discussion of which he introduces the notion – involves the use of analogy. To explicate Kant’s legislation analogy, I turn to the political theory he defended as he was writing the Groundwork, namely, the Feyerabend Lectures on Natural Law. On this basis, I argue that the autonomy of the will, as Kant conceives of it in the Groundwork, consists in the will’s being the a priori normative ground of the universal moral laws (duties) to which it is subject. Autonomy does not consist in an act by which the agent’s will gives moral laws to itself, let alone in an act by which it gives the Categorical Imperative to itself.