The relationship between feminism and sexuality in the long twentieth century is both complex and multifaceted. Whether sexuality is understood as congenital or acquired, defined by object choice or aim, central to the character of an individual or the health of a population, it is a highly contested and contradictory set of discourses and institutional practices. Feminism is similarly impossible to define as a coherent ideology or political praxis. At once a historically specific political and cultural phenomenon emerging in the first decades of the twentieth century, feminism is also a highly differentiated transnational event that belies a single origin, set of beliefs, or constituency. Organized around two key historical figures–the modern girl and the feminist-as-lesbian–this essay draws on feminist, queer, and historical studies of the world-wide feminist movements of the 1910s-1930s, and of the women’s liberation era of the late 1960s and early 1970s, to trace the connections between the commodification and politicization of women’s sexuality as two axes around which the unsettled and generative relationship between modern sexuality and feminism revolves.