In this chapter, I consider the views of happiness (eudaimonia) from the perspective of soul in ancient Greco-Roman philosophical schools. I consider the specific way in which most schools connect happiness to soul: either as Aristotle, identifying happiness with the human good he defines it as soul’s activity in accordance with virtue or as the soul’s virtuous state as the Stoics. The Stoics famously consider a virtuous state of one’s soul to be sufficient for happiness, and it has been argued that Plato and Socrates subscribed to the claim earlier. Aristotle by contrast holds that having virtue is necessary although not sufficient. Virtue of soul is still necessary for happiness for the late ancient Platonist Plotinus but in Plotinus happiness belongs to the intellect not to the soul, since the soul is capable of evil as well. A happy life belongs to the intellect intrinsically and inevitably and we live happily to the extent to which we can live a life of intellect. All of the schools considered in this chapter also hold that becoming morally or ethically good is either a necessary condition for happiness as in Plotinus, or that ethically good action constitutes happiness as in the case of Aristotle.