Data are conflicting regarding the impact of weight loss on mood and anxiety in adolescent and young adult females with moderate to severe obesity (OB), who are at increased risk for mood dysfunction compared with normal-weight females (NW). We examined depressive and anxiety symptoms in 94 females 13-21 years old: 39 in the NW group (body mass index [BMI]: 5th -85th percentiles) and 55 in the OB group (BMI >40 kg/m2 or >35 kg/m2 with comorbidities). Fifteen participants in the OB group who underwent bariatric surgery (gastric bypass or sleeve gastrectomy) and 15 getting routine care were re-assessed after 6 months. The Beck Depression Inventory-II (BDI-II) and State-Trait Anxiety Inventory (STAI) assessed depressive and anxiety symptoms, respectively. The OB group had higher BDI-II and STAI T-scores (P < .0001), a higher prevalence of clinical depression and anxiety (P < .001), and reported greater suicidal ideation (P = .02) vs the NW group. The bariatric surgery and non-surgical groups did not differ for changes in BDI-II and STAI T-Scores and suicidality over 6-month follow-up, despite greater weight loss in the former. Depressive and anxiety symptoms and suicidality were more frequently observed in the OB vs NW group. These symptoms did not improve following bariatric surgery despite significant weight loss, underscoring the need to investigate determinants of emergence and resolution of these symptoms in the OB group. © 2020 World Obesity Federation.