Inmate-on-inmate violence is a serious problem in prisons and young offender institutions. However, most studies on predictors of violent misconduct have focussed on adult inmates. This study examines the perpetration of violence in multiple young offender institutions, using the self-report data of 865 male inmates. Prevalence rates indicate that violence occurs to a high extent in the institutions. Regression analyses show that both importation and deprivation variables significantly predict the perpetration of physical and sexual violence. Specifically, drug use during imprisonment, violent beliefs, and a negative inmate–staff relationship were found to increase the risk of violent misconduct. The implications of these findings are discussed.