Background: Type 2 diabetes mellitus (T2DM) is one of the most prevalent chronic diseases, and its increasing prevalence in children and adolescents is a worldwide problem. In the past ten years, the prevalence of T2DM has increased by more than two-fold. This review focuses on the recent advances in the diagnosis and treatment of T2DM in children and adolescents. Current Concepts: Pancreatic beta-cell dysfunction and insulin resistance are the key factors contributing to the development of T2DM. The diagnosis of T2DM is based on serum glucose levels or hemoglobin A1c levels. Currently, only insulin, metformin, and liraglutide (glucagon-like peptide-1 receptor agonist) have been approved for the treatment of T2DM in children and adolescents. Discussion and Conclusion: Early diagnosis and prevention of T2DM in children and adolescents are essential. Furthermore, the treatment of T2DM in children and adolescents is limited, unlike in adults. Further research is needed to evaluate the long-term efficacy and safety of the available treatments in children and adolescents with T2DM.