Monochroa tenebrella, the common plain neb, is a moth of the family Gelechiidae.

The habitat consists of open grassy areas and heathland.

Forewings unicolorous dark shining bronzy; base of costa purplish-tinged.

The larva is reddish; spots brown; head and plate of 2 black-brown.

They feed on the roots[7] and lower stems of their host plant.