This study examined the social-ecological correlates of aggressive behavior in 120 youths with autism spectrum disorder. Youths were divided into three groups based on caregiver reports of the youth's aggressive acts: youths who engaged in acts of both physical and verbal aggression, youths who engaged only in acts of physical aggression, and nonaggressive youths. Caregivers and youths completed self-report instruments and behavior rating inventories that assessed youth individual functioning, family relations, and extrafamilial factors (i.e., peer relations, academic performance). Results showed that youths who engaged in both verbal and physical aggression were characterized by poor sleep quality and victimization by peers, and their caregivers evidenced high levels of distress and avoidant coping. In contrast, youths who were physically but not verbally aggressive were distinguished by difficulties in social interaction and communication. In general, each group of youths who were aggressive experienced more problems with repetitive behaviors, family relations, and academic performance than did their nonaggressive counterparts. The implications of these findings for theory, research, and treatment are discussed. Autism Res 2019. © 2019 International Society for Autism Research, Wiley Periodicals, Inc. LAY SUMMARY: The present study demonstrated that youths with autism spectrum disorder may be classified by the types of aggressive behaviors that they exhibit: youths who are verbally and physically aggressive, physically aggressive only, or not aggressive. Compared to the nonaggressive group, both groups of youths who were aggressive experienced difficulties in their individual, family, peer, and academic functioning. Youths with both verbal and physical aggression showed the most problems in their functioning.