Students with Emotional and Behavioral Disabilities (EBDs) are often pushed out of the least restrictive schooling environment due to schools' inability to meet their unique learning needs (OSEP, 2020). School-Wide Positive Behavior Interventions and Supports (SW-PBIS) is a research-based framework for helping school teams establish social and behavioral supports. Robert Horner and George Sugai have developed several very large-scale grants which helped to establish implementation teams at the state level. Their procedures for helping schools implement these supports have resulted in one of the largest adoptions of a model in the history of US schooling. While there have been several studies analyzing the steps taken to support students at Tier One and Tier Two of the SW-PBIS framework, very little to no research exists for developing supports for Tier Three students. The present case study analyzes a school team's efforts to implement an intervention package including a Check-In-Check-Out (CICO) behavior intervention combined with a Social Thinking social skills groups for students with EBDs in a unique full-inclusion public school context. The researcher, a practicing education specialist for students with mild to high support needs, used qualitative methods to analyze the implementation process for building Tier Three supports for students with EBDs over a four-year implementation period. [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.]