| Named By: | Otto Jaekel in 1904 |
| Time Period: | Early Jurassic, 183-179 Ma |
| Location: | England, France, Germany, Luxembourg and Switzerland |
| Size: | Average around 3 to 4 meters long, depending upon the species |
| Diet: | Piscivore/carnivore |
| Fossil(s): | Over 100 specimens |
| Classification: | | Chordata | Reptilia | Ichthyosauria | Stenopterygiidae | |
| Also known as: | | Ichthyosaurus quadriscissus | Ichthyosaurus triscissus | Stenopterygius eos | Stenopterygius incessus | Stenopterygius hauffianus | Stenopterygius longifrons | Stenopterygius megacephalus | Stenopterygius megalorhinus | |
Stenopterygius is an extinct genus of thunnosaur ichthyosaur known from Europe (England, France, Germany, Luxembourg and Switzerland). Maximum length was 4 meters (13 feet).