A new species of Bambusa (Poaceae: Bambusoideae), B. nghiana V.T. Tran, sp. nov., is described and illustrated from Thanh Hoa Province, Vietnam. This species is similar to B. gurgandii K.M.Wong & Diep, but differs by its long internodes, blade auricles lobed and not spreading, and upcurved at the end, 2-4 perfect flowers, one terminal vestigial flower.