Therion circumflexum is a species of ichneumon wasp in the family Ichneumonidae.

[2] Therion circumflexum can reach a body length of approximately 14–25 millimetres (0.55–0.98 in).

In the clypeus the median apical tooth is missing and the hind tarsal claws are evenly curved.

[3] The adult parasitoid wasps of this species fly from mid-June to September.

They parasitize various moth species including small engrailed (Ectropis crepuscularia), privet hawk (Sphinx ligustri), pine hawk-moth (Sphinx pinastri), pebble prominent (Notodonta ziczac) and a number of owlet moths (Noctuidae).