Following descriptive functional assessment procedures, a brief structural analysis was used to confirm the hypothesized antecedent conditions that preceded problem behavior across three children enrolled in Head Start classrooms. A withdrawal design investigated the effectiveness of antecedent-based interventions to reduce disruptive behaviors and increase on-task behaviors. Brief structural analyses validated hypothesized antecedent conditions for each student, and functional control was demonstrated between the antecedent-based intervention and improved behavior changes. Results indicate that brief structural analysis procedures can be conducted in natural settings and that antecedent based strategies yielded effective behavior interventions for young children at risk for developing emotional disorders. Teachers reported that assessment procedures were feasible to conduct during ongoing classroom activities and strongly agreed that antecedent strategies were effective, acceptable, and easy to implement. (Contains 1 table and 6 figures.)