The Grey Langur is a species of Leaf Monkey found in Southwestern China, Laos, Myanmar, Thailand, and northern Vietnam and which was previously considered a subspecies of the Phayre's Leaf Monkey (fig.), yet is now recognized as a distinct species, based on molecular data.

It has an overall pale grey fur, a long tail, a bluish-grey face with white circles around the eyes, and white skin at the mouth. It is also similar to the Dusky Leaf Monkey (fig.), but has a lighter fur.

Like other Leaf Monkeys, Grey Langurs are herbivorous, feeding primarily on leaves, fruits and buds, and hence spend most of their lives in the canopy of trees.