The general aim of this contribution is to explore how Plato conceives the relationship between understanding and desire in human action and to establish, on this basis, the role that he attributes to the education of desire in his account of moral education. To this end, I will focus on the Symposium, where Plato pays unprece- dented attention to the ethical value of desire and its distinctive place within the psychology of moral virtue. I shall argue that the role of understanding in Plato’s moral education is not to control or to sublimate desires, but rather to inform them. It is only by integrating desires according to the understanding of beauty that the soul or moral character of the agent becomes genuinely beautiful and thus accomplishes its intrinsic erōs.