This essay analyzes the development of Girls' Studies as a field of critical inquiry. Although scholars from across the academy and around the world currently conduct girl-centered research, considerable barriers prevented the coalescence of Girls' Studies until the late twentieth century. The first section of the essay explores the marginalization of girls in youth research and feminist scholarship prior to the 1990s, two fields where one would expect girls, girlhood, and girls' culture to be of interest. The second section focuses on transformations within and outside the academy that led to the rapid growth of girl-centered research in recent years. The third section provides a map of Girls' Studies scholarship to date, including a survey of topics explored in specific disciplines and those that deserve more attention, as well as an analysis of broader trends in such research across the academy over the past fifteen years.