Behavioral interventions have been advocated for conversion disorder, but controlled trials are lacking. The authors report the case of a 12-year-old boy with conversion disorder after 3 months of persistent right arm pain and immobility whose symptoms rapidly resolved after an outpatient behavioral intervention using negative reinforcement. The importance of careful assessment, frank discussion of the diagnosis, patient and family psychoeducation, and a rehabilitative mindset are emphasized. Negative reinforcement may be a powerful tool in the management of pediatric conversion disorder, with the potential to reduce parental anxiety and prevent unnecessary physical assessments and interventions.