Redfieldius is an extinct genus of freshwater ray-finned fish that inhabited eastern North America during the Early Jurassic period.

It is the type genus and was the last surviving member of the order Redfieldiiformes, which was widespread and diverse throughout the preceding Triassic period.

Due to this, Oliver Perry Hay reclassified it into the new genus Redfieldius, named in honor of Redfield.

The body was slightly robust, oval in shape; the snout was rounded, the eyes large and the mouth was equipped with small teeth.

Redfieldius, unlike other closely related fish, had a skull heavily ornamented with tubercles, particularly the area around the orbit and the tip of the snout.