AimsWe aimed to conduct a systematic review of published studies on the incidence of type 2 diabetes in children and adolescents aged under 20 years and provide worldwide incidence estimates for 2021. MethodsWe used MEDLINE and EMBASE to identify studies reporting type 2 diabetes incidence in children and adolescents published between Jan 2000 and April 2021. We used a negative binomial regression model to develop a prediction equation to estimate incidence rates from country characteristics. We applied the resulting incidence predictions to country population data to estimate numbers of incident cases in children and adolescents by International Diabetes Federation (IDF) region and World Bank income classification group. ResultsWe estimate that there are approximately 41,600 new cases of diagnosed type 2 diabetes among children and adolescents in 2021 worldwide. Around 30% and 40% of the worldwide total incident cases are in IDF Western Pacific region and in World Bank upper-middleincome countries, respectively. The three countries with the highest estimated number of incident cases are China, India, and United States of America. ConclusionsThe number of newly diagnosed type 2 diabetes in children and adolescents is substantial.More reliable data are needed to track the incidence of type 2 diabetes in children and adolescents.4