Multiple victimization, or polyvictimization, is closely related to delinquency and crime, although few studies have studied these experiences in juvenile offenders. Therefore, the aim of this study is to present victimization rates in young offenders from a Southwestern European country. The sample consisted of 101 youth aged between 14 and 17 years, who were mainly recruited from detention centers (77.2%). From a lifetime perspective, the majority had suffered a criminal offense against the person (93.1%), exposure to community violence (95.0%), and peer victimization (86.1%). Prevalence rates for direct and indirect family violence were also high (63.4% and 43.6%). Electronic victimization reached a rate of 40.6% and sexual victimization of 15.8%. Past year experiences showed lower but similar patterns. Based on a community population criterion to define polyvictimization, 65.3% of the sample were considered lifetime polyvictims, while 41.6% were defined as past year polyvictims. Interventions to address multiple, concurrent forms of exposure to violence should be implemented in the justice system as polyvictimization has been revealed as a frequent reality in young offenders, which may result in antisocial behavior.