The Dark-backed Sibia is a slender, long-tailed bird of mountains in Myanmar, northwestern and western Thailand, and northwestern Laos. It has a black head and white underparts.
It is about 21–23 cm long, with a slender shape, narrow bill, and long tail. The upperparts are dark brown, the head is black, and the underparts are white. Some subspecies have a grayish mantle and are placed in Black-headed Sibia by some authorities.
It inhabits broadleaf evergreen forest at about 1,000–2,565 m and feeds in the treetops on insects, grubs, berries, and nectar. It is usually seen in pairs or small groups and places its nest on small outer branches.
An extinction-risk assessment has not been added yet.