乌林鸮（学名Strix nebulosa）是分布在北半球非常大型的猫头鹰。

成年乌林鸮的头部很大及圆，面部灰色，眼睛黄色，有深色圈围绕。下身浅色及有深色斑纹；上身呈灰色有淡色斑纹。它们没有耳羽，是所有猛禽中拥有最大面盘的。

乌林鸮的大小可以比美雕鸮及毛腿渔鸮。它们比这两种猫头鹰都要轻，还要不及大雕鸮及雪鸮。它们的羽毛较为蓬松，尾巴也较长，所以虽然身体较长，但却较轻。它们约长61-84厘米，雄鸟及雌鸟分别平均长67厘米及72厘米。翼展长达152厘米，雄鸟及雌鸟分别平均长140厘米及142厘米。成年的乌林鸮重700-1800克，雄鸟及雌鸟分别平均重1000克及1290克。雄鸟一般较雌鸟细小。

The great grey owl or great gray owl (Strix nebulosa) is a very large owl, documented as the world's largest species of owl by length. It is distributed across the Northern Hemisphere. In some areas it is also called Phantom of the North, cinereous owl, spectral owl, Lapland owl, spruce owl, bearded owl, and sooty owl.