My chapter is about how Lacan incorporates sexuality in his reading of Marx’s critical approach to political economy. I examine how this reading allows Lacan to consider the role of enjoyment [jouissance] in exchange and use values, reconceptualizing them as enjoyment-value and enjoyment of value. I also analyse how Lacan, resignifying psychoanalysis and not only Marxism, emphasizes the political character of Freud’s sexual economy. After examining how the relationship of the sexual with the social has been considered among various Freudian Marxist authors, I discuss some of Lacan’s ideas about the sexual-economic foundation of society. I analyse the way in which these ideas, preceded by Jean Audard and based on Claude Lévi-Strauss, connect Marxist and Freudian concepts by founding society on the patriarchal exploitation of women. Patriarchy, according to Lacan, reaches not only its apogee in capitalist modernity but also its crisis, which manifests itself symptomatically through the discoveries of Marx and Freud. I try to explain why Marxism and psychoanalysis constituted for Lacan the last strongholds of the subject, of use value and of knowledge in an increasingly automated capitalist system governed by exchange value and dominated by data and information. After glimpsing how capital monopolizes enjoyment in modern capitalist society, I will note that one must assume an enjoyment of capital to understand the Lacanian formulations in which exchange-value operates as enjoyment-value, use-value as enjoyment of value and surplus-value as an expression of a surplus-of-enjoyment [plus-de-jouir], defined as the renunciation of enjoyment in the widespread discontent in culture. These formulations will help me to outline the way in which Lacan theorizes both Freud’s sexual economy and sexuality as a principle of the social.