The vireos /ˈvɪrioʊz/ make up a family, Vireonidae, of small to medium-sized passerine birds found in the New World (Canada to Argentina, including Bermuda and the West Indies) and Southeast Asia.

[6] The resident species occur in pairs or family groups that maintain territories all year (except Hutton's vireo, which joins mixed feeding flocks).

Songs are usually rather simple, monotonous in some species of the Caribbean littoral and islands, and most elaborate and pleasant to human ears in the Chocó vireo and the peppershrikes.

[12] Observers have commented on the vireo-like behaviour of the Pteruthius shrike-babblers, but apparently no-one suspected the biogeographically unlikely possibility of vireo relatives in Asia.

Some recent taxonomic treatements, such as the IOC taxonomy followed here, include Pteruthius and Erpornis in Vireionidae,[7][8] whereas other place them in their own families Pteruthidae and Erpornidae.