In their efforts to utilize individualist psychoanalysis as a tool for understanding mass behavior, the social theorists associated with the Frankfurt School increasingly came to rely on a static, essentializing construction of sexuality which ultimately led to an equation of fascism and homosexuality. Heretofore unexamined in studies of the Frankfurt School, this equation will here serve as the starting point for a fundamental critique of the concept of sexuality developed by this influential circle of Marxist thinkers. While directed at the concept of sexuality, such a critique more importantly opens up the underlying understanding of the social and psychological realms advanced by Critical Theory. Attending to the equation of homosexuality and fascism as the central point of concern, this essay will first trace the introduction of psychoanalysis into Critical Theory through Erich Fromm and then investigate the extent of Fromm's influence on the concept of sexuality propounded by his colleagues, especially Max Horkheimer and Theodor W. Adorno. Finally, it will take up a frequently overlooked essay by Herbert Marcuse which promoted a vision of sexuality radically different from that of his associates.