A staple food, food staple, or simply a staple, is a food that is eaten routinely and in such quantities that it constitutes a dominant portion of a standard diet for a given person, supplying a large fraction of energy needs and generally forming a significant proportion of the intake of other nutrients as well.

A staple food of a specific society may be eaten as often as every day or every meal, and most people live on a diet based on just a small number of food staples. Specific staples vary from place to place, but typically are inexpensive or readily available foods that supply one or more of the macronutrients needed for survival and health: carbohydrates, proteins, fats, minerals, and vitamins. Typical examples include tubers and roots, grains, legumes, and seeds. Among them, cereals, legumes, tubers and roots account for about 90% of the world's food calories intake.

Early agricultural civilizations valued the foods that they established as staples because, in addition to providing necessary nutrition, they generally are suitable for storage over long periods of time without decay. Such nonperishable foods are the only possible staples during seasons of shortage, such as dry seasons or cold temperate winters, against which times harvests have been stored. During seasons of plenty, wider choices of foods may be available.