Alomya debellator is a species of parasitoid wasp in the family Ichneumonidae.

Alomya debellator can reach a length of 10.5–18 mm.

Adult wasps feed on aphid honeydew and nectar of Anthriscus sylvestris and Heracleum sphondylium.

The females of this parasitoid wasp lay their eggs into the caterpillars of moths, mainly Autographa gamma, Hepialus lupulinus and Euthrix potatoria.

This species prefers hedgerows and meadows.