ABSTRACT Gigantochloa multifloscula H.N.Nguyen, N.Xia & V.T.Tran, sp. nov. is described and illustrated as a new plant species that was previously treated as Gigantochloa sp. Pham, but unnamed. Based on its vegetative, inflorescence, and basic spikelets structures, Gigantochloa multifloscula sp. nov. shares characters with most other Gigantochloa species but differs in the position of florets in pseudospikelet and branches. Investigating essentially these aspects for G. multifloscula sp. nov., we found many additional characters for this genus, which indeed has mid-culm branch complement with no dominant branch, culm wall thin and florets falling together.