Sexuality is one of the few curricular areas so constrained by policy that it often fails to resemble the topic students are interested in learning about or address the pressing concerns to which it was supposedly oriented. Focused on prevention of various sorts – and this often means prevention of all sexual activity, especially for youth – the more positive lessons about what sexuality can be for self-identity, relationality, community-building, and political life remain unaddressed. Though sexuality education has attempted to address the public goods of population health and individual development, too often it has done so without making clear concepts of gender, sex, ethical relationships, pleasure, and community. This chapter traces tensions in sexuality education from the start of its status as part of the official public school curriculum in the late nineteenth century to current debates that continue to shape how sexuality is defined and taught. We highlight continuities and ruptures that have characterized the global spread of sex education, showing how much of what happens in the Global South is shaped by legacies of colonialism and American political priorities. The chapter concludes by considering emerging challenges and opportunities for progress in sex education.