Pileated gibbons have slender bodies, long arms, and no tail, as do other members of the genus Hylobates . Head and body length ranges between 440 and 635 mm.
Males are black with white hands and feet and females have blondish fur with a black cap and chest.
The majority of their diet consists of fruits, including figs. They also eat other invertebrates, bird eggs, and small birds. Pileated gibbons drink water by immersing their hands into water or against wet leaves and then licking the water from their fur. The primary group structure is the breeding pair and their offspring. Both males and females emigrate from their natal group during adolescence.