Dipterocarpus dyeri (Khmer: rôyiëng, chhë tiël pruhs, chhë tiël th'nô:r,[2] local name Kompong Thom: chhieutiel chgor,[3] name used for commercial timber and the group of trees harvested for such: keruing, Vietnamese: Dầu Song Nàng,[4] is a species of tree in the family Dipterocarpaceae found in Myanmar, Thailand, Peninsular Malaysia (Kedah, Perlis), Cambodia, Vietnam, and northwestern Borneo.

[2] The tree is a climax or late successional species, which in some secondary forests forms relatively young pure colonies.

[7] The conservation status is based on rates of habitat loss, the major threat to the taxa,[1] though in Vietnam it is cited as having a less threatened conservation status of Vulnerable.

[4] In Cambodia the wood is classified as of the 2nd best category, and is in great demand for house and boat construction.

[2] The following insects are associated with and prey on the seed of D. costatus: Alcidodes, particularly Alcidodes crassus, Pempelia, Salebria, Dichocrocis, Andrioplecta pulverula, and Andrioplecta shoreae.