Pseudorthocerida is an order of generally straight longiconic orthoceratoids with a subcentral to marginal cyrtochoanitic siphuncle composed of variably expanded segments which may contain internal deposits that may develop into a continuous parietal lining.

Apices typically have a slight to moderate exogastric curvature The Pseudorthocerida are included in a broad in-group of generally orthoconic cephalopods known as the Orthoceratoidea (Kroger 2008) along with the Ascocerida, Dissidocerida, Lituitida, and Orthocerida.

Both have siphuncles that are partly cyrochoanitic with expanded segments and internal deposits but differ in the manner in which they develop.

From this Flower (1976) concluded that the Ordovician and Silurian pseudorthocerids (sensu Sweet 1964) were derived from different orthocerids (Orthocerida) and were therefore polyphyletic.

As a result, true pseudorthocerids were limited to the Pseudorthoceratidae while the earlier Ordovician look-a-likes were retained in the Orthocerida (Michelinocerida Flower)