尔米亚湖（波斯语：دریاچه ارومیه）位于伊朗西北角的东、西亚塞拜疆两省之间，终年不干，为境内最大咸水湖，形状像一只海马（与里海相似），最长两端长140公里，最宽55公里，水域面积52,000平方公里，最深约16公尺，近年来因为蒸发与淤积，湖面逐渐缩小。

湖名因湖边的尔米亚市而来，尔米亚源自古叙利亚语，是“水的城市”之意。在1930年代初，巴列维王朝时期，因礼萨汗之名，曾经名为“礼萨耶湖”（波斯语：دریاچه رضائی），在1970年代中，改为现在的名字。

湖中有百余个岩石小岛，是各类野生候鸟（包括红鹤、鹈鹕、琵鹭、朱鹭、鹳、翘鼻麻鸭、翘嘴长脚鹬、长脚鹬、海鸥）的过境栖息地；因湖水含盐分约为海水六倍，浓度太高，不适合鱼类生存，只有一种浮游生物，丰年虾（或称卤虫，Artemia）能够生存，具经济价值。

Lake Urmia (Persian:دریاچه ارومیه‎‎, Daryāche-ye Orūmiye; Azerbaijani:اورمیا ﮔﺆﻟﻮ, Urmiya gölü) is an endorheic salt lake in Iranian Azerbaijan, Iran and near Iran's border with Turkey. The lake is between the provinces of East Azerbaijan and West Azerbaijan in Iran, and west of the southern portion of the Caspian Sea. At its full size, it was the largest lake in the Middle East and the sixth largest saltwater lake on earth with a surface area of approximately 5,200 km² (2,000 mile²), 140 km (87 mi) length, 55 km (34 mi) width, and 16 m (52 ft) depth. The lake has shrunk to 10% of its former size due to damming of the rivers that flow into it and pumping of groundwater from the area.