Gastrioceras is a goniatitid genus in the family Gastrioceratidae that lived during the late Carboniferous (Pennsylvanian and for most of the Permian.

[1] Gastrioceras is assigned to the Gastrioceratidae, a family that makes up part of the Gastriocerataceae, known in more recent references as Gastrioceratoidea.

,[1][2] The Gastrioceras shell, or conch, is subdiscoidal to subglobose in form with moderate to wide umbilicus.

[2] The suture is characterized by a ventral lobe with two attenuated prongs separated by a high median saddle.

The lateral lobe is generally nearly symmetrical, becoming attenuated on mature specimens.