This paper contrasts the situationist view of moral growth, according to which moral growth is primarily a matter of self-knowledge – specifically, understanding the situational determinants of one’s conduct – with an Aristotelian understanding of moral growth drawn from Thomas Aquinas, on which moral growth is a matter of developing virtue. Moral growth, on the latter account, foregrounds the transformation of the appetites. The transformation of the appetites is a crucial aspect of moral growth inasmuch as it is the only way in which moral agents could come to identify with a changed conception of the good. Even if virtues are rare, as situationists maintain, we must strive to develop them by undertaking to develop appetites in accord with our understanding of good conduct.