Buckwheat (Fagopyrum esculentum), or common buckwheat is a plant cultivated for its grain-like seeds and as a cover crop. The name "buckwheat" is used for several other species, such as Fagopyrum tataricum, a domesticated food plant raised in Asia.

Despite its name, buckwheat is not closely related to wheat. It is not a cereal, nor is it even a member of the grass family. Buckwheat is related to sorrel, knotweed, and rhubarb, and is known as a pseudocereal because its seeds' culinary use is the same as cereals, owing to their composition of complex carbohydrates.