2型糖尿病（英语：Diabetes mellitus type 2，简称T2DM），旧称非胰岛素依赖型糖尿病（英语：noninsulin-dependent diabetes mellitus，简称NIDDM）或成人发病型糖尿病（adult-onset diabetes），是一种代谢性疾病。特征为高血糖，主要由胰岛素抵抗及胰岛素相对缺乏引起。1型糖尿病与其为之不同的是，1型糖尿病患者身体因为胰脏里的胰岛细胞已经损坏，所以完全丧失了生产胰岛素的功能，使得他们必须依赖外在的补充剂来生存。而2型糖尿病的典型病征为多尿症、多饮症（Polydipsia）以及多食症（Polyphagia）。2型糖尿病患者占糖尿病患者中的90%左右，其余10%主要为1型糖尿病与妊娠期糖尿病，因此后者可能被误诊。因遗传因素而易患糖尿病的高危人群中，一般认为引发2型糖尿病的主要原因是肥胖症。

Diabetes mellitus type 2 is a long term metabolic disorder that is characterized by high blood sugar, insulin resistance, and relative lack of insulin. Common symptoms include increased thirst, frequent urination, and unexplained weight loss. Symptoms may also include increased hunger, feeling tired, and sores that do not heal. Often symptoms come on slowly. Long-term complications from high blood sugar include heart disease, strokes, diabetic retinopathy which can result in blindness, kidney failure, and poor blood flow in the limbs which may lead to amputations. The sudden onset of hyperosmolar hyperglycemic state may occur; however, ketoacidosis is uncommon.