In the Research Letter titled “Trends in Obesity Prevalence Among Children and Adolescents Aged 2 to 19 Years in the US From 2011 to 2020,” published online first on July 25, 2022, and in the October 2022 issue of JAMA Pediatrics, there was an error in the analyses of the mobile examination clinic (MEC) weights. During the final analysis, the weights were removed so as to include race and ethnicity as a covariate. Per the National Health and Nutrition Examination Survey, inclusion of the MEC weights is necessary to make the prevalence data nationally representative. To address this error, calculations were performed again to include MEC weights through all stages of the analyses. As a result, the updated analyses resulted in corrections to many of the prevalence rates reported in the text, Table, and Figure. In addition, the trends for increased obesity in adolescents aged 12 to 19 years, non-Hispanic White children and adolescents, and girls changed from significant to not significant. A Letter of Explanation has been published that explains the errors. This article was corrected online.