PBIS is has been consistently correlated with reductions in student exclusion including suspensions, expulsions, poor attendance, and high school dropout rates. However, school-wide strategies that do not specifically involve effective instruction in academic areas are unlikely to result in increased academic achievement. To address this reality, multi-tiered systems of support (MTSS) involving tiered intervention for both academic and behavior have become commonplace. The Academic and Behavior Response to Intervention School Assessment (ASA) was developed to assess the fidelity with which schools are implementing MTSS for Reading, Mathematics, and behavior. Using the ASA to assess MTSS fidelity across 29 schools and four years, analyses were conducted to determine the predictive validity of sub-group domain scores. The question was whether ASA scores were predictive of student outcomes in terms of suspension and of state academic achievement scores in the areas of reading, math, and language. Results show that schools with higher fidelity in the behavior domain had significantly fewer suspension events than matched comparison schools. In comparison, higher fidelity in the reading domain was associated with more students at or above proficient on both the Language Mechanics measure and the Mathematics measure, but not in Reading; and higher fidelity in the math domain was also associated with more students at proficient or above on the Language Mechanics, but not in math or reading. Results are discussed in terms of implications for the further development of fidelity assessments and future research.