Cryptoclididae is a family of medium-sized plesiosaurs that existed from the Middle Jurassic to the Early Cretaceous.

They had long necks, broad and short skulls and densely packed teeth.

The earliest members of the family appeared during the early Bajocian, and they represented the dominant group of long-necked plesiosaurs during the latter half of the Jurassic.

[3] In 2010, two supposed late Cretaceous members of the group were reclassified as other kinds of plesiosauroids.

[4] Cladogram based on Ketchum and Benson (2010):[4] Muraenosaurus Tricleidus Cryptoclidus Kimmerosaurus