The aim of the thesis is to carry out a forensic analysis of the subject ‘justice’ in the Platonic dialogues and consider the relevant academic commentaries so as to reach a conclusion on what is Plato’s Theory of Justice. In order to arrive at a comprehensive viewpoint on this topic, the thesis had to consider the ontology and metaphysics of Plato as well as the principal social and political institutions existing in ancient Athens during the 5th Century B.C. The introduction commences with an examination of the values of Homeric Greece and the influence of the warrior on societies sense of justice. This evaluation then leads to an analysis of the Sophistic teachers at that period in ancient Athens which was in tot al contrast to the prospective adopted by Plato. Thus, the thesis discusses the dialogues between Socrates, Gorgias and Callicles in the Book Gorgias, and Thrasymachus and Glaucon and other Sophists in the Republic; the purpose is to tease out the finer nuances and differences between the Sophists and Plato’s Socrates. In the chapter, Investigations on Notions of Justice in the Platonic dialogues, the nature of justice is fully discussed and analysed. This chapter includes a comprehensive appraisal of the differences between the Sophists and Plato when considering the subject of nature and convention. A core difference between them was their respective approach to ontology and this point is thoroughly investigated in this chapter and in the chapter specifically focussed on the Sophists. The use of myth and allegories by Plato in his works is explored and in particular, the myth of the Ring of Gyges and the allegory of the cave in the Republic are comprehensively discussed. A further chapter in the thesis concentrates on a Summary of Plato’s thought and his core concepts are fully articulated and appraised. 6“pre examination copy” 2021 In order to place Plato’s thought and ideas in context with later thinkers, there are separate chapters on the works of Thomas Hobbes and Frederic Nietzsche. The penultimate chapter is called Plato Conclusion and the purpose of the chapter is to show the key 5findings of Plato’s thought and ideas. Finally, the last chapter endeavours to show the key elements of Plato’s Theory of Justice and its relevance in a contemporary era. In summation, Plato believed that justice is classified as one of the four virtues and integrity, rule of law, and a civic sense of prudence have a crucial role to play at arriving at a just act. The use of prudence and the knowledge of how weak a person is that a social contract with others is re ached, thus establishing what is right and enabling that justice is valued. This forms the bond of cohesion in the community: this is the essence of Plato’s Theory of Justice.