xiv, 183 p. : ill. (some col.) / Educators are responsible for helping students develop academic and behavior skills and for creating safe environments that promote these outcomes. Achieving these outcomes has become increasingly difficult due to disruptive, anti-social student behavior. Researchers identified Positive Behavioral Interventions and Supports (PBIS) as an evidence-based approach, integrating primary, secondary, and tertiary interventions that provide benefit for students, schools, and educational communities. However, an extensive PBIS literature and research review identified a limited application of PBIS in secondary school settings. The purpose of this dissertation was to broaden the scope of research by examining the impact of PBIS on school-wide discipline outcomes and student academic performance in a secondary school setting using case study methodology. The case study was conducted in a large, urban Pacific Northwest high school that expressed interest in improving the general school expectations and positive interactions between students and staff members. Study participants were members of a student cohort from grade 9 to grade 12. The case study provided a descriptive analysis of students’ social behavior outcomes (as measured by Office Discipline Referrals, Suspensions/ Expulsions, and Attendance Rate) and their academic performance (as measured by students’ Grade Point Averages and Course Credits). An ordered time-series display was applied to analyze behavior and achievement outcome trends. Results showed an increase in students’ Grade Point Average, Course Credits, and Attendance Rate and a decrease in students’ Office Discipline Referrals and Suspensions/ Expulsions. This study’s findings are discussed in the context of its impact on students’ social engagement and academic achievement. Evidence of students’ academic and behavior outcomes has the potential to assist in the development of material and approaches to guide, replicate, and extend current PBIS practices to secondary school settings. / Committee in charge: Dr. Gerald Tindal, Chairperson; Dr. Keith Hollenbeck, Member; Dr. Scott Baker, Member; Dr. K. Brigid Flannery, Member; Dr. Nathaniel Teich, Outside Member