Purpose: To investigate the link between adolescents’ experiences of participating in a weight-loss programme and their weight status, Health-Related Quality of Life and selfconcept over 5 years. Design and Method: A qualitative study with a hermeneutic approach, focused on interpreting adolescents’ experiences. Interviews of 10 adolescents in a weight-loss programme, and their parents, three times over 5 years. The interview findings were supported by BMI-SDS (Body Mass Index standard deviation scores) and questionnaires: Health- Related Quality of Life (HRQOL), and self-concept (Beck Youth Inventories, BSCI-Y). Results: Immediately after completion of the weight-loss programme, the 10 adolescents had all lost weight and experienced other effects, e.g. more energy, making friends and... discovering commonalities, along with improved physical parameters, experienced HRQOL and self-concept. However, weight loss was difficult to maintain after completion. Some adolescents who had regained weight 1 year after completion reported lower perceived HRQOL and self-concept and also left the study. Conclusion: Weight loss can be achieved during a treatment programme for overweight adolescents, bringing lower BMI and also potential psycho-social benefits. Focus on weight loss alone may involve overlooking other positive sideeffects of the treatment. There are also overlooked negative effects: Not all participants maintained weight loss, and for regainers, some HRQOL and self-concept scores deteriorated, compared to their situation pre-programme. These negative effects are not described in other studies. Practice Implications: We encourage enhanced professional support for drop-outs and regainers, and we recommend ongoing, open-ended programmes to better retain and support adolescents and their families. Our findings indicate this would improve intervention outcomes for the entire group.