The history of modern girlhood is entwined with anxieties about cultural norms and cultural change that are foundational to "girlhood" and "girl culture." This essay sketches a history of discourses on girls, girlhood and girl culture as the necessary genealogical context for a subsequent discussion of the field of contemporary girl studies. It begins with historical perspectives on the 'girl of the period' from the nineteenth century, through the "girl of yesterday," the "it girl" to the post World War I period that coalesced the cultural conditions necessary for the teenager to take on iconic status. The second half of the article considers girlhood studies today—and in particular its interest in locating, describing and problematizing girls' voice and girls' agency. In a world increasingly perceived as "global," these are powerful starting points for thinking about what constitutes "girl studies" (or "girlhood studies" or "girl culture studies") today.