| Named By: | Agassiz in 1838 |
| Time Period: | Late Cretaceous |
| Location: | Europe |
| Size: | About 20 to 30 centimetres long |
| Diet: | Carnivore |
| Fossil(s): | Several specimens |
| Classification: | | Chordata | Actinopterygii | Perciformes | |
Sphenocephalus is an extinct genus of ray-finned fish that lived during the Cretaceous period. Fossils have been found in England and Italy.
Sphenocephalus was about 20 centimetres (8 in) long, with a rather large head, and may have resembled a modern black bass in appearance. It was one of the earliest fish to have the pelvic fins placed beneath th pectoral fins, a common feature in modern fish that improves swimming manoeuvrability. Like the modern trout-perches, it possessed a mixture of modern and primitive features, and it was probably one of the earliest perciform fish.