This thesis presents an investigation into the notion of individual responsibility as outlined in Plato s postmortem myths. In this work, the author supports the hypothesis that Platonic myths continued to influence the discussion on individual responsibility in their time, underlining the importance of the individual s agency in relation to their actions and destinies. The central objective is to understand, based on the analyzes of the dialogues Fédon, Gorgias and Republic, how Platonic eschatological myths contribute to the awareness of individual responsibility. In this thesis, these myths are seen as a kind of pedagogical tool designed to encourage citizens to forge a responsible relationship with justice and ethics. They are not just stories, but rhetorical instruments carefully crafted to influence the way citizens live and interact in their community. In short, based on an in-depth analysis of the relationship between Plato s postmortem myths and the notion of individual responsibility in ancient Greece, we will seek to show that the former had a lasting impact on the latter. The adaptations, re-readings and recreations of traditional myths operated by Plato not only enriched philosophical thought, but also instigated citizens to reflect on their own actions and choices.