This work aims to describe the place of emotions in Plato's philosophy with a special focus on his reflections on music and the eminently pedagogical orientation that he adscribes to it. Starting from an analysis of different moments of his ouvre in which the musical phenomenon is discussed, we propose to examine his theory in order to identify its distinctive features and, above all, the very particular place it occupies in his educational model, specially in regard to the case of guardians. Since it is not the discipline itself that concerns Plato, we argue that it is possible to point out that his music theory is, in fact, an ethics of music, insofar as it is oriented according to the Greek ethos, operating as a pedagogical tool that allows inducing behavioral changes in those who receive it.