The National Center on Positive Behavior Interventions and Supports (PBIS) provides professional development and technical assistance to more than 27,000 schools nationwide (OSEP Technical Assistance Center on Positive Behavioral Interventions and Supports, 2021). Although much has been documented on the impact of Tier I PBIS implementation with fidelity on student outcomes (McIntosh et al., 2023), there is a need for more research regarding Tier 3 implementation with fidelity across a school or district. Additionally, students without effective supports experience increased exclusionary discipline, and educators experience increased stress and burnout (e.g., Brunsting et al., 2022; Soares et al., 2021; Sullivan et al., 2014). To better understand the supports needed to improve outcomes for students served with Tier 3 services positively, this model demonstration examined the impact of Tier system implementation within a school implementing all three tiers. This brief examines the impact of both improved Tier 3 implementation fidelity as measured by Tiered Implementation Fidelity (TFI) and the SelfAssessment Survey (SAS) 4.0, as well as an improved implementation of individual behavior support practices with a Tier3 group with focused support as compared to Tier 3 group without focused support in a high-needs elementary school in a rural area in the northeast. The information learned from this model demonstration may assist others working in and supporting schools in similar settings.