Nietzsche repeatedly claims that Kant’s supreme moral principle, the categorical imperative, is expressive of a kind of slave morality. Paul Guyer, however, argues that a proper understanding of Kant’s conception of free agency within the boundaries of the categorical imperative reveals that Nietzsche’s criticism of slavishness misses its mark. According to Guyer, Kant, just as much as Nietzsche, rejects slavish conceptions of morality insofar as they undermine the value of self-legislation in determining ends. This paper contends that Nietzsche may in fact have a subtler conception of the categorical imperative’s slavishness in terms of the (un)realisability of our ends, which could allow his criticisms to land, and that Kantians will be responsive to.