School districts across the nation experience student behavior problems resulting in office discipline referrals, suspensions, and time spent away from instruction. This study examined the implementation (with fidelity based on the Tiered Fidelity Instrument) of positive behavior interventions and supports (PBIS) at the Tier 1 level and the effects on referral rates, suspension rates, and attendance rates in elementary schools and middle schools in a school district in the Southeastern part of the United States. Three groups of comparable elementary schools and two groups of comparable middle schools were used in the study in which a PBIS school was compared to a non-PBIS school. The data were collected from the 2016-2017, 2017-2018, and 2018-2019 school years to look for changes over time. Using a descriptive analysis, the study showed that the implementation of PBIS Tier 1 strategies decreased the referral rates each year in one elementary school and one middle school. The study also found that the implementation of PBIS Tier 1 strategies consistently decreased the suspension rates in only one PBIS elementary school. Finally, the data showed none of the PBIS elementary schools or PBIS middle schools had an increase in attendance rates each year when compared to the non-PBIS comparable school. The findings of the study may help school district leaders, school leaders, and PBIS teams leverage future professional development opportunities for PBIS implementation and data tracking methods to strengthen the use of the PBIS framework in schools. [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.]