The northern pig-tailed macaque (Macaca leonina) is a species of primate in the Cercopithecidae family. It is found in Bangladesh, Cambodia, China, India, Laos, Myanmar, Thailand, and Vietnam. Traditionally, it has been considered a subspecies of M. nemestrina. In India, it is found in south of the Brahmaputra River, in the northeastern part of the country. Its range in India extends from Assam and Meghalaya to eastern Aruanchal Pradesh, Nagaland, Manipur, Mizoram and Tripura.