Trimeresurus albolabris, the white-lipped pit viper, is a venomous pit viper species endemic to Southeast Asia.
Maximum total length males 600 mm (24 in), females 810 mm (32 in); maximum tail length males 120 mm (4.7 in), females 130 mm (5.1 in).
Head scalation consists of 10-11(12) upper labials, the first partially or completely fused to the nasal. Head scales small, subequal, feebly imbricate, smooth or weakly keeled. The supraoculars are narrow (occasionally enlarged and undivided) with 8-12 interocular scales between them. Temporal scales smooth.
Midbody has 29 (rarely 19) longitudinal dorsal scale rows. The ventral scales are 155–166 in males, 152–176 in females. The subcaudals are paired, 60–72 in males, 49–66 in females. The hemipenes are without spines.
Color pattern: green above, the side of the head below the eyes is yellow, white or pale green, much lighter than rest of head. The belly is green, yellowish or white below. A light ventrolateral stripe is present in all males, but absent in females. The end of tail is not mottled brown.