White Willow is a species of willow native to Europe and western and central Asia. The name derives from the white tone to the undersides of the leaves.

It is a medium-sized to large deciduous tree growing up to 10–30 m tall, with a trunk up to 1 m diameter and an irregular, often leaning crown. The bark is grey-brown, deeply fissured in older trees. The shoots in the typical species are grey-brown to green-brown. The leaves are paler than most other willows, due to a covering of very fine silky white hairs, particularly on the underside; they are 5–10 cm long and 0.5–1.5 cm wide. The flowers are produced in catkins in early spring, and pollinated by insects. It is dioecious, with male and female catkins on separate trees; the male catkins are 4–5 cm long, the female catkins 3–4 cm long at pollination, lengthening as the fruit matures. When mature in mid summer, the female catkins comprise numerous small (4 mm) capsules each containing numerous minute seeds embedded in white down which aids wind dispersal.

White Willows are fast-growing, but relatively short-lived, being susceptible to several diseases, including watermark disease caused by the bacterium  Brenneria salicis (named because of the characteristic 'watermark' staining in the wood) and willow anthracnose, caused by the fungus Marssonina salicicola. These diseases can be a serious problem on trees grown for timber or ornament.

It readily forms natural hybrids with Crack Willow Salix fragilis.

The wood is tough, strong and light in weight, but has minimal resistance to decay. The stems (withies) from coppiced and pollarded plants are used for basketmaking. Charcoal made from the wood was important for gunpowder manufacture. The bark was used in the past for tanning leather.