René Girard, the theoretician of society and culture, would not be classified as a philosopher in the traditional sense by many philosophers concerned with Plato’s work. The aim of this study is to show that, inspite of this, Girard’s thought can be of interest to philosophers, and that, more particularly, it provides an opportunity to look at Plato’s thoughts in a new way (at least in the area of Plato’s social theory and his conception of the human soul). The article offers a fresh view of Plato’s thoughts about the phenomenon of mimesis, exploiting several elements of Girard’s mimetic theory. In the introduction, the author sketches the basic features of Girard’s mimetic theory and explains some of the psychosocial background of Plato’s conception of mimesis. Then, on the basis of an analysis of Plato’s Republic, it is shown that Plato may not only be characterised as an intellectual forerunner of Girard’s mimetic theory, but even as the founder of thinking about the problematic of psychological mimesis. The author’s main thesis is that the Republic may be interpreted, with the help of Girard’s ideas, as a ground-breaking study of the laws of psychological mimesis and of the effects which this mechanism has at the level of psychosocial structures. It is also shown that the Republic can be understood as a grand construction of anti-mimetic organisation in relation to the individual and to society.