The problem of justice has been existing for many years now. All through the years, history is replete with significant events that marked the peoples struggle for justice. However, the problem of justice did not only exist in reality, but also in the realm of philosophy. That is perhaps why several famous philosophers presented their idea on what is justice and how to achieve it. Among them, two names are widely known – Plato and St. Augustine. This paper aimed to compare and contrast the concepts of justice of Plato and St. Augustine. A comparative method was employed to understand the concepts of justice of Plato and Augustine. The results showed that Plato and Augustine converged on justice as a virtue, as giving one’s due, as an order within man, and as an order in the society. On the other hand, Plato and St. Augustine diverged on the following: as regards justice as giving one’s due, as regards justice as an order within man, as regards justice as an order in the society.