Dipterocarpus alatus (Thai: ยางนา, rtgs: yang na, pronounced [jāːŋ nāː]; Khmer chhë tiël ba:y, chhë tiël tük, chhë tiël thom or chheuteal; Vietnamese Dau nuoc (Dau rai)) is a tropical forest tree, of dense evergreen or mixed dense forests, common in Thailand, Cambodia, Laos and Vietnam. This species has also been found in the Philippines. It often occurs gregariously along river banks and is a key planting species for regenerating deforested land around the Dong Nai river and Cat Tien National Park. This tree is an endangered species in its natural habitat.