Acting out behaviors is a hindrance to learning across the country. The school-wide positive behavior support (SWPBS) model is a behaviorally-based systems approach to addressing problem behaviors in our school today. The problem this study is designed to address is the issue that student misbehaviors and disruptions cause a loss of valuable instructional time in the classroom, which will have a negative effect on students' behavior, academic performance, and school climate. Few studies exists that examine the impact on SWPBS on academic achievement in elementary schools. This study is unique in that it was conducted at schools that had not yet implemented Common Core, which replaced a major overhaul of academic standards in Pennsylvania in the majority of schools across the nations during the period of time that this research was conducted. The purpose of this causal-comparative design quantitative study was to examine the effects of the SWPBS model on negative behavior, math achievement, and reading achievement at two elementary schools within the research setting in Pennsylvania. The quantitative portion of the study compared the behavioral archival data, Pennsylvania System of School Assessment archival data, grades three to six, in a school district in Northeastern Pennsylvania. The study compared the before and after effects of implementation of SWPBS in the two schools. Research hypotheses in this study were evaluated using descriptive analyses, line plots, and MANOVA. Descriptive analysis revealed teachers and administrators were in agreement to the SWPBS model's effectiveness, and consistently implemented the model in the classroom. During the years that the SWPBS was implemented, line plots revealed that as the fraction of disciplinary actions that were DORs decreased for Site B, this trend was paralleled with a decrease in performance on the reading section of the PSSA reading. Likewise, as the number of DORs increased at site A, the performance on both reading and mathematics appeared to increase during the years the SWPBS was implemented. MANOVA analyses revealed significant relationship between implementation of SWPBS and impact on DORs and student achievement. The results of the study are taken with caution however, as other factors may be at play that led to the current results. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com/en-US/products/dissertations/individuals.shtml.]