A wild animal or feral animal is an animal living in the wild that does not serve man as a domestic, farm, or breeding animal and thus is not domesticated. Animals living in settled areas, nested in buildings, or even parasitic animals are wild animals, even though they do not live in the wild proper, but maintain the lifestyle of a wild animal. Basically, any animal, apart from humans can be a wild animal. Wild plants represent the same principle for plants. According to a 2016 report by WWF, global wildlife populations have shrunk by an average of 68 percent since the 1970s.

Generally, the term wild animal is used to characterize animals that are not tame. Legally, "wild" animals are ownerless (no one has ownership of them) "while they are at liberty" ("in the wild"). Often, in linguistic usage, a wild animal species is contrasted with domesticated domestic species, such as wild geese, which in Europe include not only gray geese but also Canada geese, or wild ducks, which include not only mallards. Today, only the Przewalski's horses can be called real wild horses, in a broader sense the term is also used for feral domestic horses (e.g. mustangs) - Przewalski's horses as wild animals no longer exist in Europe: for some time now, only a few reintroduced specimens have been living as wild animals in Mongolia. The term wild animal includes game, but it is much broader. By game one understands exclusively wild animals, which are subject to the hunting right.

There are wild animals almost everywhere on earth, but today very few wild animals live in the wilderness, i.e. in a natural environment untouched by man. Animals each have certain demands on their habitat (food, possibility of reproduction, protection from enemies, etc.), which are often also met by the cultural landscape shaped by humans in sufficient measure. Some wild animals have even developed into cultural successors, e.g. white stork, swift, kestrel and house mouse. On the other hand, human activities (agricultural and settlement areas) have destroyed many habitats or at least greatly reduced their area. The number of wild animals that cannot escape due to their special needs will decrease to the same extent.