Vines to more than 10 m tall; branchlets orbicular or compressed orbicular in cross section, smooth, sometimes wrinkled longitudinally. Petiole 0.8-1.5 cm; leaf blade usually oblong, sometimes oblong-lanceolate or elliptic, 10-25 × 4-11 cm, leathery or nearly so, lateral veins 8-13 on each side, base rounded or broadly cuneate, apex obtuse to acute. Male inflorescences lax, once or twice branched, 2.5-6 cm; peduncle 6-12 mm; male spikes 2-3 cm × 2.5-3 mm, involucral collars 13-18, each collar with (20-)25-45 flowers plus 10-15 sterile female flowers, basal hairs forming a dense, short cushion. Female inflorescences lateral, solitary or fascicled, main axis thin, with 3 or 4 pairs of branches; peduncle 2-3 cm; female spikes 2-3 cm × ca. 4 mm, enlarging to ca. 10 cm when mature, nodes each with 5-8 female flowers, basal hairs sparse, short. Seeds yellowish brown or reddish brown, cylindric-ovoid or cylindric, (1-)1.2-1.5(-2) cm × 6.5-9(-12) mm, 1.6-1.85 × as long as wide, base rounded, sometimes contracted into a stipe to 3(-5) mm, outer coat smooth or ± longitudinally wrinkled when dried, sometimes covered with silvery scales. Pollination Apr-Jun, seed maturity Aug-Oct.

There has been some uncertainty in the exact application of this name due at least in part to the material listed by Markgraf in the protologue being heterogeneous (there are 41 syntypes), including both this taxon and Gnetum latifolium Blume. The name has also been used in SE China, especially Hongkong, for material of G. luofuense. Gnetum montanum is best characterized by the few-flowered male involucral collars and the relatively small, distinctly stipitate seeds.

The fibers from the bark of the stem are used in making gunny bags, fishing nets, and ropes; the seeds yield an edible oil, are eaten fried, and are used for making wine; the sap is used as a cold drink.

Forests; 200-2700 m. Guangdong, Guangxi, ?Hainan, S Yunnan [Bhutan, India, Laos, Myanmar, Sikkim, Thailand, Vietnam]