Kaiwhekea ([ˌkaiˈfɛkɛa]) is an extinct genus of plesiosaur from the Late Cretaceous (Maastrichtian age) of what is now New Zealand.

The holotype was discovered in 1983 by Gary Raper, an amateur fossil collector, at the base of a cliff at Shag Point, Otago.

The specimen was enclosed in a large concretion measuring c. 6.5 metres long and weighing an estimated 10 tons.

The block was split along natural seams and dragged out on a sledge (made from a car bonnet).

[4] The following cladogram shows the placement of Kaiwhekea within Elasmosauridae following an analysis by Rodrigo A. Otero, 2016:[5] Eromangasaurus carinognathus Callawayasaurus colombiensis Libonectes morgani Tuarangisaurus keyesi Thalassomedon haningtoni CM Zfr 115 Hydrotherosaurus alexandrae Futabasaurus suzukii Kaiwhekea katiki Alexandronectes zealandiensis Morturneria seymourensis Aristonectes parvidens Aristonectes quiriquinensis Terminonatator pointeixensis Elasmosaurus platyurus Albertonectes vanderveldei Styxosaurus sp.