This chapter discusses Plato’s ethics. Plato’s ethical thinking is found throughout the dialogues, from those in which Socrates shows other people that they fail to understand the claims they make about courage, friendship, or virtue to those in which he, or another person, gives long, sometimes uninterrupted speeches on a variety of topics. Ethics is treated sometimes on its own, sometimes in political contexts, and sometimes in a framework of metaphysical theorizing. Thus, when examining Plato’s ethical arguments, it is important to pay attention to their role in the dialogue in which they occur. Nonetheless, it is legitimate to extract ethics, as a subject, from the dialogues and to outline a Platonic theory of it. Differing as they do between dialogues, his discussions of ethical concerns do fall into patterns which can be brought together and seen to have a distinctive structure. The chapter first looks at his theoretical answer to the question about virtue and happiness. It then examines the way he discusses virtue, followed by an exploration of his positions on pleasure. It concludes by looking at the relation of Plato’s ethics to his political and his metaphysical thought.