The ancient antwren (Herpsilochmus gentryi) is a species of tropical bird in the family Thamnophilidae.

Females and subadults display whitish or yellow spots on the crown and generally have darker olive breasts and sides than adult males.

[4] Ancient antwren can be distinguished from this species by its brighter yellow or olive underparts and lack of any rufous on the head or breast.

This species is restricted to humid terra firme forest in north-central Peru and southeastern Ecuador within the Amazon basin.

The breeding season is believed to be early in the year, from January to March, based on skull ossification of juvenile birds and sightings of family groups in April.

[2] The ancient antwren forages high in canopy or sub-canopy, where it gleans prey from leaves and branches.

[2] This species has been documented to forage in mixed flocks with other canopy-dwelling birds, as well as in small family groups or mated pairs.

The ancient antwren's song is described as a long decelerating series of notes that rises slightly in frequency, then decreases.