Recent years have seen unprecedented interest in girls’ activism, and yet our understanding of their politics is still limited. More broadly, children have largely been absent from International Relations scholarship, despite the centrality of childhood and our understandings of it to global politics. Where they have featured, it is often as victims of phenomena beyond their control, or as the perpetrators of crimes, but rarely as active subjects able to influence politics for the better. In this article, I review the emerging literature that aims to conceptualise girls’ agency in global politics. I show the parallels between recent work in Girlhood Studies and in feminist and postcolonial IR, in exploring the potential for feminist activism within and against neoliberalism. Finally, I outline how a ‘transnational girlhoods’ approach might enable feminist scholars to explore how girls across a range of different contexts are challenging inequalities