Craniopharyngioma is a relatively rare, benign tumor that most often affects pre-adolescent children. Surgical resection is a common form of treatment, which may result in adverse physical, neurological, and behavioral effects, most notably, aggressive behavior. In this case study we describe a typically developing 6 year old female who had resection of a craniopharyngioma and subsequently developed severe aggressive behavior that interfered significantly with her recovery and functioning. Results of a functional analysis indicated that her aggression was maintained by contingent escape from task demands and access to preferred food items. A highly structured behavioral intervention, consisting of differential reinforcement of alternative behaviors, together with extinction targeted to each function of the behavior, was effective in reducing her aggression to below 88% of baseline levels. Her adaptive behaviors also increased significantly. These results suggest that assessment and treatment utilizing principles of applied behavior analysis can ameliorate the occurrence of problem behavior following craniopharyngioma resection.