Acer oblongum is a medium-sized evergreen to semi-deciduous tree reaching a height of approximately 15-22 mt. Unique among maples, this plant stays green all winter. The trunks are buttressed, with a smooth to wrinkled bark. Leaves are opposite, ovate-lanceolate with entire margin and petiolated, 5-12 cm long, with glaucous-green underside and dark green upperside. The young shoots are reddish bronze and finely hairy. The flowers are hermaphrodite, small and inconspicuous, about 4 mm, greenish white, gathered in hairy racemes. The fruits are represented by the typical two-winged samaras, about 2.5 cm long, wind dispersed. It has been introduced for its wood and it is sometimes cultivated in large gardens for its evergreen foliage.