Diabetes Mellitus (DM) encompasses a spectrum of metabolic disorders characterized by elevated blood glucose levels, primarily due to defects in insulin secretion, insulin action, or both. Type 1 DM results from autoimmune destruction of pancreatic beta cells, leading to absolute insulin deficiency. Type 2 DM involves insulin resistance in target tissues combined with inadequate insulin secretion. Gestational DM occurs during pregnancy and increases the risk of Type 2 DM later in life. Other specific types include genetic defects affecting beta cell function, diseases of the pancreas, and drug-induced diabetes. Understanding these classifications is crucial for tailored management strategies and prevention efforts against the global burden of diabetes mellitus and its associated complications.