In two studies, the systematic approach to designing functional assessment-based interventions (FABIs) created by Umbreit, Ferro, Liaupsin, and Lane (2007) was used with high school students receiving special education services in self-contained classrooms reserved for students with persistent behavior problems. In Study 1, an AB design was used with a male student with high rates of off-task behavior. In Study 2, an ABAB design was used with a female student exhibiting inappropriate language. Results from both studies indicated that a multi-component FABI can decrease target behaviors for high school students. Treatment fidelity data indicated that a less complicated intervention may increase the accuracy with which interventions are implemented. Brief discussions of each study as well as an overall discussion synthesizing findings across studies are included.