The place in Mill’s work where the concept of autonomy seems most obviously relevant is in the argument of chapter III of On Liberty – and it on this chapter that I focus. Here, Mill argues that human beings should be allowed to live in accordance with their own natures, rather than ideals imposed externally. I outline his argument in section I, and the place of autonomy in Mill’s overall scheme of values, or “Art of Life”. In section II, I consider what it means to be governed by one’s own nature. As I note, in arguing that we should live according to our own nature, Mill does not intend to suggest that we should obey the diktats of an inbuilt pre-social essence. Rather, he has in mind that we live according to what he terms a ‘second nature’ shaped by processes of acculturation. To be autonomous in this sense, of course, involves socialised into certain modes of life, and questions arise as to what kinds of socialisation is truly compatible with autonomy. I conclude, in section III, by attempting to give an indication of Mill’s approach to this issue.