Troedssonellidae is a family of orthoceroid cephalopods from the Ordovician, derived from rod-bearing Baltoceratidae, that have a continuous lining within the siphuncle that resembles very thin and slender endocones.

The siphuncle is central or subcentral, composed of straight or slightly expanded segments.

Septal necks generally short and connecting rings are thin.

[1][2] Troedsonnellids first appear high in Lower Ordovician (Cassinian) strata, beginning with Tajaroceras and extend at least through the Whiterock Stage of the Middle Ordovician.

[2][3] They also may have given rise to the Striatoceratidae and to the Narthecoceratidae of the Middle and Late Ordovician.