Legislation penalizing animal cruelty recognizes both intentional acts of cruelty and neglect, the failure to act to care for an animal. All fifty American states have such statutes, but they vary widely on the definition of animal, ranging from all living creatures to vertebrates or mammals.

The first legal writing against animal cruelty was part of the social reform movement of the early 19th century, when reformers such as Jeremy Bentham argued that "The question is not, Can they reason? nor, Can they talk? but Can they suffer."

Animal cruelty has been linked to Domestic Violencedomestic violence. Issues in animal cruelty cases include cosmetics testing, laboratory testing, marketing of animal furs and leathers, endangered species, and the treatment of animals in rodeos, circuses, zoos and wildlife parks. Current animal protection law covers commercial animal fighting, endangered species law, pet trusts, animal rights laws, veterinary practices and laboratory testing of animals, in addition to animal cruelty.

American Humane Society (10.5 million members), People for the Ethical Treatment of Animals (1.8 members worldwide), The Humane Society of the United States, Progressive Animal Welfare Society, Society for the Prevention of Cruelty to Animals, Royal Society for the Prevention of Cruelty to Animals.