The Pine Marten (Martes martes) is an animal in the weasel family, native to Europe. Note, the American Marten (Martes americana) is also called a pine marten in North America.

The Pine Marten is around the size of a domestic cat. Its body is up to 53 cm in length, its bushy tail can be 25 cm. Males are slightly larger than females; on average a marten weighs around one and a half kilograms. Their fur is usually dark brown and grows longer and less coarse during the winter months. They have a cream colored "bib" marking on their throats.

Martens are the only mustelid with semi-retractable claws. This enables them to lead more arboreal lifestyles, although they are also relatively quick runners. They are thought to be mostly nocturnal. They prey on small mammals, birds, insects, frogs, and carrion. They have also been known to eat berries, bird's eggs, and honey. Although they are preyed upon occasionally by golden eagles and even more rarely by red foxes; humans are their most formidable adversaries. Martens are prized for their furs.

The pine marten has lived to 18 years in captivity, but in the wild lifespans of three to four years are more typical. They reach sexual maturity at two or three years of age. The young are usually born in March or April after a month-long gestation period in litters of three or so. Young pine martens weigh around 30 grams at birth. Their eyes open at around five weeks of age.