The silvery-flanked antwren (Myrmotherula luctuosa) is an insectivorous bird in subfamily Thamnophilinae of family Thamnophilidae, the "typical antbirds".

[2] The silvery-flanked antwren was described by the Austrian ornithologist August von Pelzeln in 1868 and given its current binomial name Myrmotherula luctuosa.

Adult males have a medium gray head, neck, back, and rump with a hidden white patch between the shoulders.

Their wings are blackish with white tips on the coverts and gray edges on the flight feathers.

It inhabits the understorey to mid-storey of evergreen forest and secondary woodland (including restinga).

It forages singly, in pairs, or in family groups, and often as part of a mixed-species feeding flock.

[9] The silvery-flanked antwren's breeding season is not well known but appears to span from July to January.

The silvery-flanked antwren's song "begins and ends with short harsh...notes, middle ones become longer and clearer, pace slows then speeds up, intensity increases then decreases, pitch is flat and notes countable".