寡尿（英文：Oliguria），指排尿的量比正常人少。

寡尿的定义因年龄差异而有所不同。

• 在婴儿：尿量少过1 mL/kg/h
• 在儿童：尿量少过0.5 mL/kg/h
• 在成人： 一天尿量少过400 mL

Oliguria or hypouresis (both names from roots meaning "not enough urine") is the low output of urine. In humans, it is clinically classified as an output more than 80 ml/day but less than 400ml/day. The decreased output of urine may be a sign of dehydration, kidney failure, hypovolemic shock, HHNS hyperosmolar Hyperglycemic Nonketotic Syndrome, multiple organ dysfunction syndrome, urinary obstruction/urinary retention, DKA, pre-eclampsia, and urinary tract infections, among other conditions.