The Rio Suno antwren (Myrmotherula sunensis) is a species of bird in subfamily Thamnophilinae of family Thamnophilidae, the "typical antbirds".

[2] The Rio Suno antwren has two subspecies, the nominate M. s. sunensis (Chapman, 1925) and M. s. yessupi (Bond, J, 1950).

Adult males of the nominate subspecies are mostly gray with a hidden white patch between the shoulders.

Subadult males are like adult females with some black starting to show on the throat and breast.

Subspecies M. s. yessupi is found in east-central Peru's departments of Huánuco and Pasco and into southwestern Brazil at least to the Rio Juruá.

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

It occurs in a few protected areas "but more survey work is needed in order to permit a better assessment of the true distributional limits and status of this species".