Gonystylus affinis is a tree in the family Thymelaeaceae.
Gonystylus affinis grows as a tree up to tall, with a trunk diameter of up to . The bark is reddish brown. The fruit is also reddish brown, up to in diameter.
Gonystylus affinis is native to Peninsular Malaysia and Borneo. Its habitat is lowland forests to altitude.
Gonystylus affinis has been assessed as vulnerable on the IUCN Red List. The species is threatened by logging, insufficient replanting and habitat loss to palm oil plantations. In Indonesia, the species is threatened by increasing frequency of fires.