[1] Stephanids are noted for their ocellar corona, a semicircular to circular set of projections around the middle ocellus, forming a "crown" on the head.

Weakly developed grooves starting at the base of the antennae and extending past the eyes to the back of the head capsule are present.

One species, Schlettererius cinctipes, is a known parasitoid of horntail wasps and has been introduced to Tasmania as a biological pest control agent.

[2] Members of the genus Foenatopus are parasitoids of Agrilus sexsignatus, wood-boring beetle larvae found infesting eucalyptus in the Philippines.

The oldest confirmed members of the family are Kronostephanus zigrasi, Lagenostephanus lii, and Phoriostephanus exilis all known from the Late Cretaceous (Cenomanian) Burmese amber.

The first species to be described from the fossil record was Protostephanus ashmeadi, which was first published in 1906 by paleoentomologist Theodore Dru Alison Cockerell.