The laboratory mouse or lab mouse is a small mammal of the order Rodentia which is bred and used for scientific research or feeders for certain pets. Laboratory mice are usually of the species Mus musculus. They are the most commonly used mammalian research model and are used for research in genetics, physiology, psychology, medicine and other scientific disciplines. Mice belong to the Euarchontoglires clade, which includes humans. This close relationship, the associated high homology with humans, their ease of maintenance and handling, and their high reproduction rate, make mice particularly suitable models for human-oriented research. The laboratory mouse genome has been sequenced and many mouse genes have human homologues. Lab mice sold at pet stores for snake food can also be kept as pets.

Other mouse species sometimes used in laboratory research include two American species, the white-footed mouse (Peromyscus leucopus) and the North American deer mouse (Peromyscus maniculatus).