Summary Background Paediatric obesity disproportionately impacts individuals from minoritized racial and ethnic backgrounds. Recent guidelines support use of anti‐obesity pharmacotherapy for adolescents with obesity, but the potential impact on disparities in obesity prevalence has not been evaluated. Objectives To model changes in obesity prevalence with increasing utilization of anti‐obesity pharmacotherapy among adolescents. Methods Data representative of American adolescents ages 12–17 years were obtained from the National Health and Nutrition Examination Survey, cycles 2011 through pre‐pandemic 2020. A body mass index (BMI) reduction of 16.7% was applied to each participant based on clinical trial results of weekly subcutaneous semaglutide 2.4 mg among adolescents. Utilization disparities were based on utilization of the same medication class among adults. Obesity prevalence was calculated assuming utilization of 10%–100%, stratified by race and ethnicity. Results Among 4442 adolescents representing 26 247 384 American adolescents, projected overall obesity prevalence decreased from 22.2% to 8.4% with 100% utilization. However, disparities increased relative to Non‐Hispanic White youth, with prevalence among Non‐Hispanic Black and Mexican American youth ranging from 40%–60% higher to 90%–120% higher, respectively. Conclusions Increasing utilization of anti‐obesity pharmacotherapy may widen relative disparities in obesity, particularly if utilization is unequal. Advocacy for equitable access is needed to minimize worsening of obesity‐related disparities.