Positive Behavior Intervention Support (PBIS) has been used in many schools as an effective behavior management system to improve the behavior of students in classrooms, which impacts their academic performance. This quantitative, retrospective, one-group pretest posttest study was to determine the impact of PBIS on students' academic and behavior performance in a Title I school in the United States, via purposeful archival data of 55 elementary students. Theories such as (a) ecological theory, (b) social cognitive theory, (c) social learning theory, and (d) Theory X and Theory Y guided the study. These theories were selected due to their relevance to PBIS practices and student performance. The archival student data collected for this study included the Criterion Referenced Competency Test (CRCT) and office discipline referral data. One-tailed t-tests analyses were performed to compare pretest post-test scores to (a) examine the impact of PBIS on students' behavioral and academic performance and (b) inspect if students' academic performance differed by gender. All analyses revealed no significance differences (p > 0.05) -- neither in students' academic nor in their behavioral performance, after a two-year engagement in PBIS activities. The findings further revealed that gender had no impact on the performance of students. Surprisingly, these findings contradict those of other studies on PBIS and student performance, thereby, imploring the scientific community to embrace future research. Still, the results may be used by organizational leaders in their decision-making processes, as they seek to implement PBIS practices, in an effort to improve the performances of their members. [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://bibliotheek.ehb.be:2222/en-US/products/dissertations/individuals.shtml.]