Animal slaughter is the killing of animals, usually referring to killing domestic livestock. It is estimated that each year, 80 billion land animals are slaughtered for food. Most animals are slaughtered for food; however, they may also be slaughtered for other reasons such as for harvesting of pelts, being diseased and unsuitable for consumption, or being surplus for maintaining a breeding stock. Slaughter typically involves some initial cutting, opening the major body cavities to remove the entrails and offal but usually leaving the carcass in one piece. Such dressing can be done by hunters in the field or in a slaughterhouse. Later, the carcass is usually butchered into smaller cuts.

In livestock agriculture and the meat industry, a slaughterhouse, also called an abattoir, is a facility where livestock animals are slaughtered to provide food. Slaughterhouses supply meat, which then becomes the responsibility of a meat-packing facility.