Girls' bodies are often constructed negatively and passively in their dominant cultures, but at the same time, girls may collectively construct menstruation and the body in creative ways. By exploring menstrual talk in individual and group interview data from mostly white, high school age girls and boys in the US, this study finds that girls draw on their bodies in social interaction to exert agency in their negotiations with the gendered world and social structure. These types of agency are based within the girls' sense of responsibility and management of menstruation, their knowledge of menstruation and their social interpretations of menstruation.