An extensive body of empirical evidence indicates that function-based behavior support plans are likely to be more effective and efficient in school settings than plans that are not function-based. Designing technically adequate behavior support plans, however, is not sufficient to ensure that these plans will be implemented with fidelity by school staff. The contextual “fit” of support plan procedures with the values, skills, resources and administrative support of implementing personnel also affects the likelihood of implementation. In this dissertation a single-subject concurrent multiple baseline design across participants was used to examine the efficacy of the Contextual Fit Enhancement Protocol (CF Intervention). The CF Intervention was designed to improve the contextual fit of support plans for four elementary school students with problem behaviors. This CF Intervention was designed based on the assumption that when procedures included in a plan match the values, skills, administrative support and resources of the people responsible for implementation the plans will be implemented with higher fidelity and will be more likely to produce desired student outcomes. Results from the study indicate that after implementation of the CF Intervention, support plans that were already technically adequate improved in contextual fit: instructional staff (a) had a better understanding of behavioral procedures being used, (b) received specific, systematic feedback about its implementation, (c) perceived high levels of administrative support, and (d) perceived a collective commitment to improve current plans. Following implementation of the CF Intervention, substantial increases in implementation fidelity and decreases in student problem behavior were observed. In addition, teacher participants rated the CF Intervention process as effective and efficient. Limitations and implications for future research, practice, and training are discussed.