The Nothosaurus - an extinct reptile species - also known as the "false lizard", was a medium-sized sauropterygian genus of the Triassic. Fossil finds have so far been made in Europe and Asia.

The Nothosaurus looked like a giant lizard. The largest species were measured at up to seven meters with a skull length of 60 cm.

The lifestyle of the Nothosaurus could have been similar to that of modern seals. It was probably more adapted to life in the sea and gave birth to its offspring alive and in the water - as has also been proven for ichthyosaurs.