The Tenasserim langur is notable for an upright crown crest and white rings around the eyes. Available sources say its habitat preferences and range limits remain unclear.
The studied animal had grayish-black, unsilvered fur, slightly lighter underneath, and a dark-gray tail. The tail base and area around the sitting pads were whitish; its gray face had a violet tinge and fully encircling white eye-rings.
The Thailand zoo account says the langur's habitat preference is unclear. It lists records from mixed deciduous dipterocarp forest and moist evergreen forest.
An extinction-risk assessment has not been added yet.