The Plain-winged Antwren is suspected to be most closely related to the Ashy Antwren (Myrmotherula grisea) of the southern tropical Andes, on account of their similar vocalizations, habitat preferences, and morphology. Males are principally gray above and below, with a broad black throat patch, and females are largely warm brown, becoming more olive over the crown, with a duskier tail and a pale throat. The species possesses a highly disjunct range, in the pantepui region of southern Venezuela, adjacent northernmost Brazil, and the Guianas, with a dramatically isolated, and probably much smaller, population in south-central Colombia to northeast Ecuador. Throughout this overall range, the Plain-winged Antwren inhabits the lower and mid strata of montane and foothill forest. Four subspecies are generally recognized, and these differ most noticeably in females.