Objective: To report a case of an adolescent with autism with clinically significant hypersexual behaviors in whom a trial of low-dose propranolol led to major clinical improvement. Case Summary: This case report describes a 13-year-old boy with a history of autism who presented to the outpatient psychiatric clinic for hypersexual behaviors that started at the onset of puberty. The behaviors affected his functioning both at school and home. A trial of low-dose propranolol, 0.3 mg/kg/d (10 mg twice a day), targeting hypersexual behavior led to remarkable clinical improvement. The behaviors remained stable on this dose of propranolol for 1 year. Discussion: Hypersexual behavior exhibited by adolescent patients with autism can be a big challenge to manage. The literature on pharmacological options to manage these behaviors in children and adolescents with autism is limited. Clinical data of propranolol use are novel. Conclusion: To our knowledge, this is the first case report of low-dose propranolol leading to clinically significant improvement in hypersexual behaviors in an adolescent with autism. Propranolol use may expand the choice of treatment option in this patient population.