[1] It was formerly considered a subspecies of the Cat Ba langur (T. poliocephalus), which is now thought to be endemic to Vietnam.

[2] Its taxonomy was previously uncertain; it has been considered a partially albinistic population of the François' langur (T. francoisi), a subspecies of Francois' langur,[3] a valid species (T. leucocephalus), or a subspecies, T. poliocephalus leucocephalus.

[1][4][2] Populations of the white-headed langur in Chongzuo and Fusui County display notable genetic divergence from the rest of the species, and it has thus been proposed they be treated as evolutionarily significant units.

[5] The white-headed langur has a very small range in the province of Guangxi in southernmost China, endemic to karst hills, where it is known from a few scattered populations.

Habitat fragmentation and anthropogenic land modification have negatively affected this, while other reasons may include its relatively short evolutionary history and restricted population size.