| Named By: | Traquair in 1836 |
| Time Period: | Carboniferous 330-300 Ma |
| Location: | Ireland (Republic of, and Northern) and Scotland |
| Size: | Possibly as much as 6 to 7 meters long |
| Diet: | Carnivore/Piscivore |
| Fossil(s): | Several individuals but usually only of partial remains |
| Classification: | | Chordata | Osteichthyes | Sarcopterygii | Tetrapodomorpha | Rhizodontida | Rhizodontidae | |
Rhizodus (root tooth) is an extinct genus of rhizodont, a branch of the Sarcopterygii, the bony vertebrate clade that also includes tetrapods. It reached 6-7 metres (20-23 ft) in length.