The 1997 reauthorization of the Individuals with Disabilities Education Improvement Act made major changes to the education of children with disabilities who exhibit challenging behavior. The law emphasized the use of positive behavior supports (PBS) and functional behavioral assessments (FBA) as a strategy to address challenging behavior. Since then, evidence demonstrating the effectiveness of PBS in reducing challenging behavior among school students has been widely disseminated in the research literature. In spite of the emergence of literature on the use of PBS practices, questions remain concerning the functional utility of PBS within schools and widespread adoption among school personnel. There are several factors that may be inhibiting the adoption of this relatively new evidence-based technology in schools. The purpose of this study was to examine difficulties that school teachers face in the implementation of PBS in their classrooms and schools. (Contains 6 tables.)