This essay discusses the views of Peter Olivi (ca. 1248-98) on the foundations of political power and agency. The central argument is that there is a strong connection between Olivi’s voluntarist psychology and his views concerning political power. According to Olivi, political power is ultimately based on the will of God, but in such a way that both the rulers and their subjects have, through their individual freedom, the liberty to use their share of power as they will. In fact, Olivi conceptualises political power as an extension of the dominion that human beings have over their wills, which is essential for being a political agent in the full sense. By providing a philosophical analysis of the role of the freedom of the will within Olivi’s political philosophy, this essay sheds light on his conception of the relation between the human and the divine will, as well as on his understanding of political power.