The increased prevalence of adolescent obesity and associated short-term and long-term complications emphasize the need for effective treatment. In this Review, we aim to describe the evidence for, and elements of, behaviour management and adjunctive therapies and highlight the opportunities and challenges presented by obesity management in adolescence. The broad principles of treatment include management of obesity-associated complications; a developmentally appropriate approach; long-term behaviour modification (dietary change, increased physical activity, decreased sedentary behaviours and improved sleep patterns); long-term weight maintenance strategies; and consideration of the use of pharmacotherapy, more intensive dietary therapies and bariatric surgery. Bariatric surgery should be considered in those with severe obesity and be undertaken by skilled bariatric surgeons affiliated with teams experienced in the medical and psychosocial management of adolescents. Adolescent obesity management strategies are more reliant on active participation than those for childhood obesity and should recognize the emerging autonomy of the patient. The challenges in adolescent obesity relate primarily to the often competing demands of developing autonomy and not yet having attained neurocognitive maturity.