They are generally small, slender, yellow, brown or black coloured flies.

The larval food plants are grasses, including cereal crops, the adults are mainly found in open habitats.

R1 is short, the subcosta ends near the break of the costa (usually incomplete but apical part sometimes visible as a faint line reaching the costa) and near apex of R1;posterior basal wing cell and anal cell are small.

The larvae live in the stems of grasses, a few species being a pest in agriculture, for instance Opomyza florum, the Yellow Cereal fly.

Damage caused by Opomyzidae to Gramineae is termed "dead heart".