A mouse (plural mice) is a small mammal belonging to the order of rodents. The best known mouse species is the common house mouse (Mus musculus). It is also a popular pet. The American white-footed mouse (Peromyscus leucopus) and the deer mouse (Peromyscus maniculatus) also sometimes live in houses. In some places, certain kinds of field mice are also common. This rodent is eaten by large birds such as hawks and eagles. They are known to invade homes for food and occasionally shelter.

Although mice may live up to two and a half years in captivity, the average mouse in the wild lives only about four months, primarily owing to heavy predation. Cats, wild dogs, foxes, birds of prey, snakes and even certain kinds of arthropods have been known to prey heavily upon mice. Nevertheless, because of its remarkable adaptability to almost any environment, and its ability to live commensally with humans, the mouse is regarded to be the second most successful mammalian genus living on Earth today, after humans.

Mice can at times be harmful rodents, damaging and eating crops, causing structural damages and spreading diseases through their parasites and feces. In North America, breathing dust that has come in contact with mouse excrements has been linked to hantavirus, which may lead to Hantavirus Pulmonary Syndrome (HPS).

Primarily nocturnal animals, mice compensate for their poor eyesight with a keen sense of hearing, and rely especially on their sense of smell to locate food and avoid predators. The original motivation for the domestication of cats is thought to have been for their predation of mice and their relatives, the rats.