The beech marten, also known as the stone marten, house marten or white breasted marten, is a species of marten native to much of Europe and Central Asia, though it has established a feral population in North America. It is listed as Least Concern on the IUCN Red List on account of its wide distribution, its large population, and its presence in a number of protected areas. It is superficially similar to the European pine marten, but differs from it by its smaller size and habitat preferences. While the pine marten is a forest specialist, the beech marten is a more generalist and adaptable species, occurring in a number of open and forest habitats.

A marten is a weasel-like mammal in the genus Martes within the subfamily Guloninae, in the family Mustelidae. They have bushy tails and large paws with partially retractile claws. The fur varies from yellowish to dark brown, depending on the species; it is valued by animal trappers for the fur trade. Martens are slender, agile animals, adapted to living in the taiga, which inhabit coniferous and northern deciduous forests across the Northern Hemisphere.