长尾叶猴（英文：Northern Plains Gray Langur；学名：Semnopithecus entellus），又名长尾猴、白猴、白脸猴、雪猴，属于猴科长尾叶猴属，是叶猴中体型最大的一种，体长约70cm，体重约20kg。以几乎与身长相当甚或更长的尾部得名。主要分布于**聂拉木、樟木、吉隆、朋曲河谷、西绒辖河谷、亚东、墨脱、马藏布河谷、波曲河谷、吉隆河谷、门隅、洛渝等地。

The northern plains gray langur (Semnopithecus entellus) is a species of primate in the family Cercopithecidae. It is found in India on the lowlands north of the Godavari and Krishna rivers and south of the Ganges. It is thought to be introduced to western Bangladesh by Hindu pilgrims on the bank of the Jalangi River. Its natural habitats are subtropical or tropical dry forests and subtropical or tropical dry shrubland. It is threatened by habitat loss.