Breakfast cereal is a breakfast food made from processed cereal grains. It is traditionally eaten as part of breakfast, or a snack food, primarily in Western societies.

Barley, a member of the grass family, is a major cereal grain grown in temperate climates globally. It was one of the first cultivated grains; it was domesticated in the Fertile Crescent around 9000 BC, giving it nonshattering spikelets and making it much easier to harvest. Its use then spread throughout Eurasia by 2000 BC. Barley prefers relatively low temperatures to grow, and well-drained soil. It is relatively tolerant of drought and soil salinity, but is less winter-hardy than wheat or rye.