Hay is grass, legumes, or other herbaceous plants that have been cut, dried, and stored for use as animal fodder, particularly for grazing animals such as cattle, horses, goats, and sheep. Hay is also fed to smaller animals such as rabbits and guinea pigs. Pigs may be fed hay, but they do not digest it as efficiently as more fully herbivorous animals.

Háy is a Hungarian surname. Notable people with the surname include:

• Gyula Háy (1900–1975), Hungarian communist leader
• László Háy (1893–1975), Hungarian economist
• Peter Háy (author) (born 1944), Canadian author, son of Gyula Háy

Hay is dried grass.