Over the past decade, policymakers have enforced increasingly greater accountability demands for student achievement and zero tolerance policies. Legislators have outlined proficient measures for student achievement which includes students enrolled in general and special education classes and all ethnicities and socioeconomic levels. Schools strive daily to meet these standards while dealing with student behavioral issues that interfere with this goal. On average, student disruptions resulted in a loss of at least one hour a day leading to a substantial amount of instructional time per school year. Educators must explore creative strategies to address these disruptions to preserve instructional time. Therefore, the purpose of this quantitative study was to add to the repertoire of research-based strategies designed to assist educators in addressing classroom disruptions that interfere with the learning process. This study examined the impact of Positive Behavior Interventions and Supports (PBIS) on student behavior and academic achievement. Data was collected for 702 seventh grade students from three middle schools for a two year period. Students' discipline referrals and Measures of Academic Progress (MAP) scores in reading and mathematics were analyzed to determine if there was a significant difference in ISS and OSS assignments and students' performance on MAP before and after PBIS. Data analysis was also extended to examine the effect on race, gender, and socioeconomic status. The results indicated that PBIS was effective as a school-wide approach to disruptions; particularly with students of low socioeconomic backgrounds. Additionally, student achievement improved after PBIS as a result of changed teacher and student behavior. PBIS had a positive impact on males and all ethnicities. [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.]