Aerophagia is a functional gastrointestinal disorder characterized by excessive swallowing of air associated with abdominal distension and pain, flatulence, belching, nausea, and vomiting. The purpose of the current study was to evaluate the effectiveness of an antecedent-based behavioral intervention on aerophagia with an adolescent female diagnosed with Lennox-Gastaut syndrome (LGS), severe intellectual disability, and herpes simplex virus infection of the central nervous system with chronic static encephalopathy. Results from a functional analysis and multiple-component aerophagia assessment suggested that aerophagia persisted in the absence of social consequences (i.e., maintained by automatic reinforcement), and was sensitive to activity-based antecedent manipulations. Results from the behavioral treatment evaluation yielded clinically and statistically significant decreases in aerophagia with behavioral treatment alone, and with combined behavioral-pharmacological treatment.