This study evaluatedthe short-term impact of a school-based violence prevention initiative on developmentalprocesses thought to place children at risk for future aggression and violence and examined theinfluence of classroom and neighborhood contexts on the effectiveness of the violenceprevention initiative. Two waves of developmental data (fall and spring) were analyzed from the1st year of the evaluation of the Resolving Conflict Creatively Program (RCCP), which includes5053 children from grades two to six from 11 elementary schools in New York City. Threedistinct profiles of exposure to the intervention were derived from Management InformationSystem (MIS) data on between classroom differences in teacher Training and Coaching inRCCP, Classroom Instruction in RCCP, and percentages of students who are Peer Mediators.Developmental processes that place children at risk were found to increase over the course of theschool year. Children whose teachers had a moderate amount of training and coaching fromRCCP and who taught many lessons showed significantly slower growth in aggression-relatedprocesses, and less of a decrease in competence-related processes, compared to children whoseteachers taught few or no lessons. Contrary to expectation, children whose teachers had a higherlevel of training and coaching in the RCCP but taught few lessons showed significantly fastergrowth over time in aggressive cognitions and behaviors. The impact of the intervention onchildren's social cognitions (but not on their interpersonal behaviors) varied by context.Specifically the positive effect of High Lessons was dampened for children in high-riskclassrooms and neighborhoods. Implications for future research on developmentalpsychopathology in context and for the design of preventive interventions are discussed.