Polyptychodon (meaning 'many-folded tooth') is a genus of pliosaurid found in Middle-Late Cretaceous marine deposits in southern England, France and Argentina.

[2] The type species, P. interruptus is known from an isolated tooth from the Late Cretaceous Chalk Group of southern England.

[1] Owen described a second nominal species of the genus, P. continuus, from an isolated tooth collected in the Hythe Formation of Maidstone, Kent.

[3] Comparison between Albian-age isolated vertebrae from marine deposits in France and Kronosaurus suggested a size of approximately 7 metres (23 ft) for a Polyptychodon-like brachaucheniine pliosaurid.

[4] The species Polyptychodon patagonicus (Ameghino, 1893), based on crocodile teeth discovered in Argentina, shares the same genus name.