This study A Critique of Just State in Plato examined the criticism of Just State in Plato's Republic. Plato's conception of justice is informed by his conviction that everything in nature is part of a hierarchy, and that nature is ideally a vast harmony, a cosmic symphony, every species and every individual serving a purpose. In his philosophy Plato gives a prominent place to the idea of justice. Plato was highly dissatisfied with the prevailing degenerating conditions in Athens. This study criticised Plato's view on Just State. The major objective of this work was to criticize the Just State in Plato's Republic. The research method adopted in this research include, the expository, analytic and critical methods. The study pointed out certain shortcomings in Plato's theory of Ideal State. Plato draws an analogy between the individual and the state, but it is confusing. The Ideal State is absolute and totalitarian. The scheme of communism is impracticable. Plato's advocacy of communism of family on eugenic ground is ridiculous, absurd and fantastic. Plato, in his Ideal State, fails to denounce the evil institution of slavery. Conclusively, Plato's just state in his idea of justice and social class has been both an inspiration and warning for subsequent efforts in utopian projects. His work has been subjected to criticism as it has a lot of criticism which has been put together in this study. Even though criticized, his ideas still pledge to be useful if its rational parts are adopted to solve basic problems.