Very little is known about the influence of the social-psychological context on children's aggressive behavior. The purpose of this research was to examine the interrelations of group contextual factors and the occurrence of aggressive behavior in 22 experimental play groups of 7- and 9-year-old African-American boys. Group context was examined before, during, and after an aggressive act as well as during nonaggressive periods. The results showed that there are dimensions of group context (i.e., negative affect, high aversive behavior, high activity level, low group cohesion, competitiveness) that were related to the occurrence of aggressive behavior between 2 children in the group. Group context influenced how children reacted to aggression between its members (e.g., siding with the victim), which in turn influenced the quality of the postaggression group atmosphere. This study suggests that individual-within-context information be incorporated into theories of aggression among children.