The possibility of a harmony between the psychological doctrine of Aristotle and that of Plato marks a significant issue within the context of the debate surrounding Aristotle’s putative opposition to or harmony with Plato’s philosophy. The standard interpretation of Aristotle’s conception of the soul being purely hylomorphic leaves no room for harmonisation with Plato, nor does a functionalist interpretation that reduces Aristotle’s psychological doctrine to physicalist terms. However, these interpretations have serious drawbacks, both in terms of ad-hoc explanations formulated in the developmentalist mode, and the misconstruing of some of the fundamental features of Aristotle’s psychological doctrine. A dualist interpretation that accepts Aristotle’s doctrine of some part of the soul being properly incorporeal, separable and immortal overcomes these drawbacks and, significantly, opens the door for Platonic harmonisation. Furthermore, it can be shown that the kind of immortality in question is also in line with the Platonic stance, due to a deep similarity between the conceptions of metaphysical and moral personhood held by Plato and his student. However, this Aristotelian dualism is not Platonic dualism simpliciter. Rather, it is best understood in terms of the division of labour between Aristotle and Plato suggested by the Neoplatonic commentators generally, and Simplicius in particular. I argue that though questions surrounding these issues and particularly the issue of reincarnation remain, an account of Aristotle’s psychological doctrine as dualist and in harmony with Plato’s view of the soul can be shown to be stronger than both standard hylomorphic and functionalist accounts, both exegetically and philosophically.