Youth violence is a topic of increasing global concern. Research has primarily focused on young people's responses to existing definitions of violence in seeking to understand how best to develop violence prevention. Little work has explored how young people themselves define violence and the factors which influence their acceptance, and use, of violent behaviour. The present study investigated young people's understandings of what constitutes violence, their acceptance of violence and justifications made for doing so. The study was distinct in its focus on young people's characterisations of violence. The findings revealed that gender norms mediate understandings of what constitutes violence and discourses around the perceived acceptability of violence. Particular forms of violence were clearly identified as being more acceptable and "deserved" than others and young people's perceptions were shaped by their understandings of appropriate and normative gender behaviour.