Summary Mental health after bariatric surgery during adolescence has been little explored. This is a sensitive period in terms of self‐image on which bariatric surgery could have negative effects because of the rapid and significant changes in morphology it induces. Previous studies have explored mental effects using questionnaires and only related to psychopathological disorders. The objective of our study was to complement these studies by exploring, via in‐depth interviews, the adolescents' views on changes after bariatric surgery at psychological as well as socio‐emotional levels. Fourteen adolescents with obesity were recruited in a French hospital 6–43 months after surgery. They participated in one‐on‐one interviews lasting an average of 45 minutes. A lexical analysis (using ALCESTE software © ) of their speech highlighted the most positive effects, particularly in terms of social relationships, physical activities, self‐esteem and reduced stigma, along with less positive effects in terms of eating behaviour and skin. In terms of clinical implications, this study confirmed the value of bariatric surgery for adolescents at psychological and social levels and its contribution to their mental health. However, it also highlighted the importance of pre‐ and post‐operative support.