In this paper, I analyse the different declinations of the concept of parrhesia. First, I perimeter the framework of the question: Foucault deconstructs the modern concept of truth and identifies the normative nature of the structures that legitimise it. Going back to ancient times, Foucault rediscovers the alethurgical forms through which the subject speaks its truth. One of these is parrhesia. The three declinations that Foucault studies refer to different contexts in ancient history.