The bicolored antvireo (Dysithamnus occidentalis) is a Near Threatened insectivorous bird in subfamily Thamnophilinae of family Thamnophilidae, the "typical antbirds".

Adult males of the nominate subspecies D. o. occidentalis have a blackish gray head, upperparts, and tail with a mostly-hidden white patch between the scapulars.

Their face, throat, and breast are dark grey with thin white streaks; their belly and crissum are olive-brown.

It is found on the Pacific slope of the Andes from southern Antioquia Department in Colombia south into Carchi Province in extreme northern Ecuador.

Subspecies D. o. punctitectus is found on the Andes' eastern slope separately in Ecuador's Napo and Morona-Santiago provinces and Peru's Amazonas and San Martín departments.

It was an open cup made of fungal fibers and twigs in a branch fork and partially hidden by overhanging leaves.

[9] Schulenberg et al. describe a vocalization in San Martín, Peru, as a song, "an accelerating, descending series of clear rising whistles: WEE wee-wee-wee-whe'he'huhu".

It occupies a limited number of sites within its disjunct range, and its estimated population of between 7300 and 8000 mature individuals is believed to be decreasing.

It occurs in some nominally protected areas in Colombia but all are either surrounded by cleared land or being encroached upon by human settlement.