Functional behavioral assessment (FBA) was developed and researched in clinical settings as an effective strategy to identify interventions that both manage inappropriate behavior and teach appropriate replacement behavior, but is it equally effective in school settings, which typically involve much less structure and much greater social complexity? This study investigated the efficiency and efficacy of function-based interventions as compared to traditional interventions that were not function-based. Interventions were compared across 4 students in a multitreatment single-subject design; results demonstrated clear and immediate decreases in problem behavior with the introduction of function-based interventions and similarly strong increases with each introduction of non-function-based intervention. These results add a more stringently controlled example in support of the efficacy of function-based intervention. (Contains 4 figures and 1 table.)