While much work has shown that aggressive and disruptive behavior in schools may be reinforced by friends and, for some individuals, enhanced social status in the classroom, few studies have examined these phenomena at school entry. This study sought to examine aggressive behavior patterns in kindergarten children in relation to other individual characteristics, peer affiliations, and classroom social positions. Subgroups of aggressive-unpopular and unaggressive-popular children were found, while a group of aggressive-popular students was not evident. Both aggressive and popular children tended to belong to groups composed of similar associates, indicating selective affiliation on these characteristics. Results are discussed in terms of their implications for intervention with and prevention of aggressive behavior through elementary school. (Contains 4 tables.)