水曲柳（学名：Fraxinus mandschurica）为木犀科梣属的植物。

落叶大乔木；小枝对生有四棱；奇数羽状复叶，卵状长圆形小叶7－11枚，基部楔形，不对称，边缘有锯齿，下面沿着脉和小叶基部密生黄褐色绒毛，叶轴微有翅；圆锥花序腋生，雌雄异株，夏季开花。

Fraxinus mandshurica (Manchurian Ash) is a species of Fraxinus native to northeastern Asia in northern China (Gansu, Hebei, Heilongjiang, Henan, Hubei, Jilin, Liaoning, Shaanxi, Shanxi), Korea, Japan and southeastern Russia (Sakhalin Island).

It is a medium-sized to large deciduous tree reaching 30 m tall, with a trunk up to 50 cm in diameter. The leaves are 25–40 cm long, pinnate compound, with 7-13 leaflets, the leaflets 5–20 cm long and 2–5 cm broad, subsessile on the leaf rachis, and with a serrated margin. They turn to a golden-yellow in early autumn, and the tree is usually early to change color. The flowers are produced in early spring, before the new leaves, in compact panicles; they are inconspicuous with no petals, and are wind-pollinated. The fruit is a samara comprising a single seed 1–2 cm long with an elongated apical wing 2.5–4 cm long and 5–7 mm broad.