Mesochorus is a genus of ichneumonid wasps (Hymenoptera: Ichneumonidae) containing approximately 900 species which are generally hyperparasitoids of ichneumonid or braconid wasps, or occasionally of tachinid flies. The hosts of Mesochorus are generally endoparasitoids of larval insects such as Lepidoptera and Coleoptera. Only one species is currently described from Australia, of which the holotype can not be located. In 2022, students at Elliston Primary School in South Australia collected a specimen of Mesochorus in a Malaise trap as part of the citizen science project Insect Investigators. We here describe Mesochorus baccanellonyah Fagan-Jeffries, sp. nov. from this single specimen, both for the greater meaning this species name has to the community, and to help inspire future work on this genus in Australia.