Criminology has an incomplete and imprecise understanding of the qualitative aspects of juvenile co-offending. This article explores one type of juvenile crime, namely arson. Using publicly available judicial records, it analyses 60 cases of fire-setting in Sweden in which there were two or more perpetrators aged under 21 acting jointly. The resulting categorization shows the social organization of juvenile fire-setting to be centred around nine different positions that a young person can take during the planning, preparation and commission phase of an arson offence. The findings highlight the usefulness of bringing together criminological research on co-offending and juvenile fire-setting to better understand the dynamics driving and facilitating youth arson and group aspects of youth delinquency and crime more generally.