This paper examines how educators, police and children’s service providers, alongside young people, conceptualise the nature and causes of sexual harm among young people. Drawing on qualitative research conducted in southeast England, we identify four themes: sexual harm as learned behaviour rooted in personal and familial risk factors; normalisation of harmful experiences among girls; neglect and minimisation of boys’ victimisation; and evolving digital terrains of harm. While some participants engaged with structural and cultural explanations, many framed sexual harm through an individualised, risk-focused behaviourist lens. We suggest the emphasis on behaviour within the prevailing use of the term “harmful sexual behaviour” reinforces reductionist perspectives and overlooks interactional, institutional, and socio-cultural dynamics shaping young people’s experiences. Drawing on sexual script theory and post-digital sexual citizenship, we expand the conceptual terrain, advocating for a holistic and inclusive approach situating sexual harm within broader relational and institutional contexts, requiring nuanced, context-sensitive responses.