Meat is animal tissue, mostly muscle, that is eaten as food. Humans have hunted and farmed other animals for meat since prehistory. The Neolithic Revolution allowed the domestication of vertebrates, including chickens, sheep, goats, pigs, horses, and cattle, starting around 11,000 years ago. Since then, selective breeding has enabled farmers to produce meat with the qualities desired by producers and consumers. Meat is important to economies and cultures around the world.

Meat is mainly composed of water, protein, and fat. Its quality is affected by many factors, including the genetics, health, and nutritional status of the animal involved. Without preservation, bacteria and fungi decompose and spoil unprocessed meat within hours or days. Meat is edible raw, but it is mostly eaten cooked, such as by stewing or roasting, or processed, such as by smoking or salting.

The consumption of meat (especially red and processed meat, as opposed to fish and poultry) increases the risk of certain negative health outcomes including cancer, coronary heart disease, and diabetes. Meat production significantly harms the environment by contributing to global warming, pollution, and biodiversity loss. Some people (vegetarians and vegans) choose not to eat meat for ethical, environmental, health or religious reasons.

The word meat comes from the Old English word mete, meaning food in general. In modern usage, meat primarily means skeletal muscle with its associated fat and connective tissue, but it can include offal, here meaning other edible organs such as liver and kidney. The term is sometimes used in a more restrictive sense to mean the flesh of mammalian species (pigs, cattle, sheep, goats, etc.) raised and prepared for human consumption, to the exclusion of fish, other seafood, insects, poultry, or other animals.

Paleontological evidence suggests that meat constituted a substantial proportion of the diet of the earliest humans. Early hunter-gatherers depended on the organized hunting of large animals such as bison and deer. Animals were domesticated in the Neolithic, enabling the systematic production of meat and the breeding of animals to improve meat production.

In the postwar period, governments gave farmers guaranteed prices to increase animal production. The effect was to raise output at the cost of increased inputs such as of animal feed and veterinary medicines, as well as of animal disease and environmental pollution. In 1966, the United States, the United Kingdom and other industrialized nations, began factory farming of beef and dairy cattle and domestic pigs. Intensive animal farming became globalized in the later years of the 20th century, replacing traditional stock rearing in countries around the world. In 1990 intensive animal farming accounted for 30% of world meat production and by 2005, this had risen to 40%.

Modern agriculture employs techniques such as progeny testing to speed selective breeding, allowing the rapid acquisition of the qualities desired by meat producers. For instance, in the wake of well-publicized health concerns associated with saturated fats in the 1980s, the fat content of United Kingdom beef, pork and lamb fell from 20–26 percent to 4–8 percent within a few decades, due to both selective breeding for leanness and changed methods of butchery. Methods of genetic engineering that could improve the meat-producing qualities of animals are becoming available.

Meat production continues to be shaped by the demands of customers. The trend towards selling meat in pre-packaged cuts has increased the demand for larger breeds of cattle, better suited to producing such cuts. Animals not previously exploited for their meat are now being farmed, including mammals such as antelope, zebra, water buffalo and camel, as well as non-mammals, such as crocodile, emu and ostrich. Organic farming supports an increasing demand for meat produced to that standard.