The main aim of this study was to examine the extent to which affective and cognitive empathy were associated with reactive and proactive aggression, and whether these associations differed between children with an Autism Spectrum Disorder (ASD) and typically developing (TD) children. The study included 133 children (67 ASD, 66 TD, M age = 139 months), who filled out self-report questionnaires. The main findings showed that the association between reactive aggression and affective empathy was negative in TD children, but positive in children with ASD. The outcomes support the idea that a combination of poor emotion regulation and impaired understanding of others' emotions is associated with aggressive behavior in children with ASD. (Contains 1 figure and 4 tables.)