Obesity in adolescence will probably have major implications not only for the affected adolescents but also for society. Those who have obesity during adolescence usually have obesity into adulthood, which causes many medical and psychological issues that can result in premature death. Furthermore, obesity in adolescents is associated with a range of social problems, including difficulties securing an apprenticeship or a job or finding a partner. Adolescents with obesity are also at increased risk of having children with obesity later in life. All these consequences lead to high costs for the health-care system. Although efficient treatment options are available that have been proven in randomized controlled trials, such as lifestyle interventions for adolescents with obesity and bariatric surgery for adolescents with severe obesity, these interventions frequently fail in clinical practice as treatment adherence is low in adolescents and most adolescents with obesity do not seek medical care. Therefore, improving treatment adherence and identifying treatment barriers are necessary.