In this article, we examine the different ways in which Thomas Szasz and Michel Foucault have challenged dominant perspectives within psychiatry. We identify, analyze, and compare the central elements of their respective discourses on psychiatry and show that although they are often bracketed together, in fact there are certain fundamental differences between Szasz and Foucault. Of most importance is their contrasting ways of characterizing the nature and role of critical thought. Whereas Szasz’s analysis is predicated on a number of binary distinctions, Foucault works to overcome such distinctions. In the past ten years, a new movement of critical psychiatry has emerged. Although this shares certain concerns with the critical psychiatry of the 1960s and 1970s, there are substantial differences. We argue that this discourse is more resonant with the Foucauldian approach.