Duabanga grandiflora is native to Cambodia, Eastern India, Laos, Malaysia, Myanmar, Thailand, and Vietnam where it is found in evergreen rain forests between 900-1500 m in elevation.
It is found in open forests including vegetation adjacent to riverbanks and in valleys. The genus Duabanga contains only two other species including Duabanga moluccana, and a cultivated, proposed hybrid species Duabanga x taylorii. Duabanga x taylorii is unusual as it is known only in cultivation at the Royal Botanic Gardens in Peradeniya, Sri Lanka. It was grown from seed obtained from an unknown source and is thought to have come from Indonesia, however, its geographic origin and its proposed hybrid origin cannot be confirmed.
(Haining, Q. S. Graham, and M.G. Gilbert. Lythraceae. In Flora of China 13: 274-276)