Although boys too are involved in relational aggression, their experiences are overshadowed by the focus on relational aggression among girls. This paradox mirrors the empirical puzzle that forms the starting point for this article: while teachers saw relational aggression as a 'girl problem', we found a vast undercurrent of relational aggression among boys. Drawing on ethnographic fieldwork and interviews with staff and students in Norwegian schools, we ask how boys' relational aggression can be left unnoticed by school staff. We demonstrate that there is a gap between the experiences boys have of being victims of relational aggression and their expression of this, in terms of both their inability to talk about it and its undramatic form. We argue that this represents a blind spot for school staff and for the boys themselves, and suggest that gendered knowledge production contributes to reproducing the invisibility of relational aggression among boys.