The mountain tapir is a medium-sized mammal with an average length from head to tail of 180 cm and a height at shoulder level of 90 cm. It has a thick, dark coat that protects it from the low temperatures that prevail in its habitat. Like other tapirs, it has three hooves on its hind legs and four on its front legs. There is no marked sexual dimorphism, although mature females are usually larger than males of similar age.
The most developed senses are the sense of smell and hearing, while their eyesight seems less developed. It has a striking fringe of white hair around its lips and when it reaches maturity shows a hairless area on the lower back, where a kind of shiny callosity is formed.