Two studies examined the interactive effect of receptive verbal intelligence measured by the Peabody Picture Vocabulary Test and self-regulatory competencies measured in the delay of gratification paradigm on boys’ aggression. Study 1 participants (N=98) were middle school, low-income boys primarily ethnic minority. Participants for Study 2 (N=59) were drawn from a treatment camp for boys from low-income neighborhoods with behavioral adjustment problems. In both studies, the interaction between verbal intelligence and self-regulation was significant such that verbal intelligence was associated with lower aggression to a greater extent among boys who had effective self-regulatory skills than among those who had ineffective self-regulatory skills. The implications of these findings for interventions and for a theory of risk factors in aggression are discussed.