The focus of this project is on intervention research to promote preschoolers' social behavior and emotional development, one of the five developmental domains important for children's social competence and school readiness (National Educational Goals Panel, 1999). Many early school problems children have are related to many of the same underlying risk factors noted in studies of social and emotional behavior problems among seriously disruptive children. Furthermore, the risk factors that are associated with the development of social and emotional problems are more likely to be found in families and communities that Head Start programs typically serve (i.e., low income communities with limited resources; families that may be disorganized, experiencing higher than normal rates of emotional, economic, or marital stress). The present study is designed to reduce behavior problems and improve socioemotional functioning in young children through an intervention, which enhances the provision of supportive mental health services, basic overall classroom quality, parent involvement, and specific classroom strategies. The proposed intervention is a modification of the Preschool Behavior Project, an evidence-based intervention program for aggression requiring intensive intervention with parents and teachers by highly-trained and supervised clinical consultants (Bryant, Vizzard, Willoughby & Kupersmidt, 1999). Unlike most intervention programs, we have implemented the PBP in Head Start and have preliminary evidence supporting its effectiveness in reducing disruptive behavior and thereby improving classroom functioning. The goal of the current project is to develop and evaluate a less intensive, but still effective, self-sustaining intervention that ultimately can be implemented as a broad quality improvement strategy by the existing Head Start T/TA network.