This chapter examines Michel Foucault’s work on sexuality, power, and prisons. It also explores Foucault’s lectures on biopower, race, and government. This chapter discusses his analysis of discourses and truth before considering the concept of power that informed his approach to sexuality and prisons. Critical questions about this concept raised in his 1975–1976 lectures ‘Society Must Be Defended’ led to its eventual abandonment in favour of a concept of power as government. The chapter then discusses the ideas of biopower and race raised in the final chapter of The History of Sexuality before taking up his approach to liberal and neoliberal government in Security, Territory, Population (2007) and Birth of Biopolitics (2008) and the concept of power outlined in the light of this approach. The conclusion summarizes Foucault’s impact on thought and politics around sexuality and the wider impact of his work on power, biopower, and government.