| Named By: | Tamaki Sato in 2003 |
| Time Period: | Late Cretaceous, Campanian |
| Location: | Canada, Saskatchewan - Bearpaw Formation |
| Size: | Estimated at 7 meters long. Possibly 9 meters long if it had a neck of proportionate length to some other elamosaurids. Skull is 26.8 centimetres long |
| Diet: | Piscivore |
| Fossil(s): | Skull and partial articulated skeleton, possibly of a sub adult |
| Classification: | | Chordata | Reptilia | Sauropterygia | Plesiosauria | Elasmosauridae | |
Terminonatator (meaning "last swimmer") is a genus of elasmosaurid plesiosaur from the Late Cretaceous of Saskatchewan, Canada. It is known from a skull and partial skeleton from a young adult, found in the Campanian-age Bearpaw Formation near Notukeu Creek in Ponteix. Terminonatator is currently one of the youngest plesiosaurs from the Western Interior Seaway.