The sable (Martes zibellina) is a species of marten, a small omnivorous mammal primarily inhabiting the forest environments of Russia, from the Ural Mountains throughout Siberia, and northern Mongolia. Its habitat also borders eastern Kazakhstan, China, North Korea and Hokkaido, Japan.

The name "sable" originates from Slavic languages and entered Western European languages through the medieval fur trade. Sables are small, omnivorous mammals that inhabit dense forests in regions like Russia, Mongolia, and China. They are known for their luxurious fur, which ranges from light to dark brown and is softer and silkier than that of American martens. Sables resemble pine martens in size and appearance but have more elongated heads, longer ears, and shorter tails. They are skilled climbers and primarily hunt by sound and scent. Mating occurs between June and August, and litters typically have two or three offspring. Sable fur has been highly valued in the fur trade since the early Middle Ages, and its popularity has driven hunting and conservation efforts. Today, sable fur is often used to decorate clothing items, and the species has no special conservation status according to the IUCN Red List.

The name sable appears to be of Slavic origin and entered most Western European languages via the early medieval fur trade. Thus the Russian соболь (sobol') and Polish soból became the German Zobel, Dutch sabel; the French zibeline, Spanish cibelina, cebellina, Finnish soopeli, Portuguese zibelina and Medieval Latin zibellina derive from the Italian form (zibellino). The English and Medieval Latin word sabellum comes from the Old French sable or saible.

The term has become a generic description for some black-furred animal breeds, such as sable cats or rabbits, and for the colour black in heraldry.

Males measure 38–56 centimetres (15–22 in) in body length, with a tail measuring 9–12 centimetres (3.5–4.7 in), and weigh 880–1,800 grams (1.94–3.97 lb). Females have a body length of 35–51 centimetres (14–20 in), with a tail length of 7.2–11.5 centimetres (2.8–4.5 in). The winter pelage is longer and more luxurious than the summer coat. Different subspecies display geographic variations of fur colour, which ranges from light to dark brown, with individual coloring being lighter ventrally and darker on the back and legs. Japanese sables (known locally as クロテン or kuroten) in particular are marked with black on their legs and feet. Individuals also display a light patch of fur on their throat which may be gray, white, or pale yellow. The fur is softer and silkier than that of American martens. Sables greatly resemble pine martens in size and appearance, but have more elongated heads, longer ears and proportionately shorter tails. Their skulls are similar to those of pine martens, but larger and more robust with more arched zygomatic arches.

Sables inhabit dense forests dominated by spruce, pine, larch, Siberian cedar, and birch in both lowland and mountainous terrain. They defend home territories that may be anything from 4 to 30 square kilometres (1.5 to 11.6 sq mi) in size, depending on local terrain and food availability. However, when resources are scarce they may move considerable distances in search of food, with travel rates of 6 to 12 kilometres (3.7 to 7.5 mi) per day having been recorded.

Sables live in burrows near riverbanks and in the thickest parts of woods. These burrows are commonly made more secure by being dug among tree roots. They are good climbers of cliffs and trees. They are primarily crepuscular, hunting during the hours of twilight, but become more active in the day during the mating season. Their dens are well hidden, and lined by grass and shed fur, but may be temporary, especially during the winter, when the animal travels more widely in search of prey.

Sables are omnivores, and their diet varies seasonally. In the summer, they eat large numbers of mountain hare and other small mammals. In winter, when they are confined to their retreats by frost and snow, they feed on wild berries, rodents, hares, and even small musk deer. They also hunt ermine, small weasels and birds. Sometimes, sables follow the tracks of wolves and bears and feed on the remains of their kills. They eat gastropods such as slugs, which they rub on the ground in order to remove the mucus. Sables also occasionally eat fish, which they catch with their front paws.