Cruelty to animals, also called animal abuse, animal neglect or animal cruelty, is the infliction by omission (neglect) or by commission by humans of suffering or harm upon non-human animals. More narrowly, it can be the causing of harm or suffering for specific achievements, such as killing animals for entertainment; cruelty to animals sometimes encompasses inflicting harm or suffering as an end in itself, referred to as zoosadism.

Divergent approaches to laws concerning animal cruelty occur in different jurisdictions throughout the world. For example, some laws govern methods of killing animals for food, clothing, or other products, and other laws concern the keeping of animals for entertainment, education, research, or pets. There are several conceptual approaches to the issue of cruelty to animals.

Even though some practices, like animal fighting, are widely acknowledged as cruel, not all people and nations have the same definition of what constitutes animal cruelty. Many would claim that docking a piglet's tail without an anesthetic constitutes cruelty. Others would respond that it is a routine technique for meat production to prevent harm later in the pig's life. Additionally, laws governing animal cruelty vary from nation to nation. While it is routine practice in the United States, docking a piglet's tail as part of regular practice is prohibited in the European Union (EU).

It may be said that there is nothing inherently wrong with using animals for human purposes, such as food, clothing, entertainment, and research, but that it should be done in a way that minimizes unnecessary pain and suffering, sometimes referred to as "humane" treatment. In contrast, some have argued that the definition of 'unnecessary' stated above varies widely and could include virtually all current use of animals.

Utilitarian advocates argue from the position of costs and benefits and vary in their conclusions as to the allowable treatment of animals. Some utilitarians argue for a weaker approach that is closer to the animal welfare position, whereas others argue for a position that is similar to animal rights. Animal rights theorists criticize these positions, arguing that the words "unnecessary" and "humane" are subject to widely differing interpretations and that animals have basic rights. They say that most animal use itself is unnecessary and a cause of suffering, so the only way to ensure protection for animals is to end their status as property and to ensure that they are never viewed as a substance or as non-living things.