Two prospective studies examined a theoretical model wherein exposure to victimization, resulting from early behavioral risk, heightens children's social alienation and subsequent deviant peer affiliation (DPA). Across Study 1 (298 girls, 287 boys; K–7th grade; 5–12 years) and Study 2 (338 girls, 298 boys; 2nd–6th grade; 8–12 years), children, parents, peers, and teachers reported on children's externalizing behavior and internalizing symptoms, peer victimization, social alienation, and DPA. Path analyses supported the proposed pathway: Peer victimization predicted social alienation, which then predicted DPA. Early externalizing behavior set this path in motion and made an independent contribution to DPA. This research identifies an important pathway through which externalizing behavior and consequent peer victimization launch children onto a risky social trajectory.