An integrative model is proposed for understanding the development of physical and relational aggression in early and middle childhood. The central goal was to posit a new theoretical framework that expands on existing social-cognitive and gender schema models (i.e., Social Information-Processing Model of Children's Adjustment [N. R. Crick & K. A. Dodge, 1994] and the Schematic-Processing Model of Sex Role Stereotyping [C. L. Martin & C. F. Halverson, 1981]). The proposed model suggests several individual- and group-level effects and the available evidence for each of these hypotheses is discussed. The ways in which the proposed model may guide future research in the field are presented. (Contains 1 figure.)