Kopsia rajangensis is a tree in the family Apocynaceae.

The specific epithet rajangensis refers to the Rajang River in Borneo, near which the species was initially surveyed.

[3] Kopsia rajangensis grows as a shrub or small tree up to 5 metres (20 ft) tall.

Its flowers feature a white corolla.

[3] Kopsia rajangensis is endemic to Borneo, where it is confined to Sarawak.