There is a dearth of research on the long-term efficacy and safety of treatments for adolescent obesity. This narrative review examined several approaches to treatment, focusing on long-term effectiveness data in adolescents, as well as relevant findings from studies of adults. The available research suggests that lifestyle modification has promise in obese adolescents, although it is not clear that any particular dietary or physical activity approach is more effective than another. Meal replacements are quite effective in adults and deserve further research in adolescents. Extending the length of treatment to teach weight loss maintenance skills is likely to improve long-term outcomes in adolescents, and delivering treatment via the Internet or telephone is a novel way of doing so. Treatment that combines lifestyle modification with the medication orlistat generally appears to be safe but only marginally superior to lifestyle modification alone. More research is needed on the management of adolescent obesity, which has been overlooked when compared with research on the treatment of obesity in children and adults.