Pseudocarapa crassa is a tree in the family Meliaceae. The specific epithet ' is from the Latin meaning 'thick', referring to the parts of the flowers.
The tree grows up to tall with a trunk diameter of up to . The bark is fawn-coloured to dark purplish brown. The sweetly scented flowers are pale green to creamy-white. The fruits are round, at least in diameter.
Pseudocarapa crassa is endemic to Borneo. Its habitat is dipterocarp and kerangas forests from to elevation.