This action research project evaluated a program for improving student discipline and developing a positive classroom environment. The targeted populations consisted of prekindergarten, first-, and fifth-grade students in two middle class suburbs of Chicago (Illinois). Changes in behavior were documented through behavior checklists, parental contact logs, discipline referrals by teachers to the principal, and teachers' anecdotal records. Analysis of probable cause data revealed that inappropriate behavior was related to lack of discipline plans in the classroom, the changing family structure, overcrowded schools, inclusion of special needs students, and the influence of television and other media. A review of solution strategies yielded the selection of three major components of intervention. These components were a clear classroom discipline plan developed by teachers, instruction in problem solving and intrapersonal decision-making skills, and regular positive reinforcement strategies. As a result of the interventions, the students decreased both acts of insubordination and acts of physical aggression by as much as 76 percent. Off-task behavior was decreased by as much as 63 percent. The students decreased assignment incompletion by as much as 71 percent. Finally, the students became better problem-solvers as a result of the interventions. (Eighteen appendices present observation and classroom materials. Contains 19 references.) (Author/JPB)