Rye (Secale cereale) is a grass grown extensively as a grain, a cover crop and as a forage crop. It is a member of the wheat tribe (Triticeae) and is closely related to barley (Hordeum) and wheat (Triticum). Rye grain is used for flour, rye bread, rye beer, crisp bread, some whiskeys, some vodkas, and animal fodder. It can also be eaten whole, either as boiled rye berries, or by being rolled, similar to rolled oats.

Rye is a cereal grain and should not be confused with ryegrass, which is used for lawns, pasture, and hay for livestock.