Acuetzpalin (meaning "water lizard" in Classical Nahuatl) is an extinct genus of platypterygiine ophthalmosaurid ichthyosaur found in the Kimmeridgian[1][2] La Casita Formation in Mexico.

Its length is estimated to have been more than 3.1 metres (10 ft) long, considering the missing parts of the holotype.

A phylogenetic analysis conducted in 2020 reveals that Acuetzpalin is a member of the subfamily Platypterygiinae and is located among the most-derived platypterygiines.

[3] The following cladogram shows a possible phylogenetic position of Acuetzpalin in Ophthalmosauridae according to the analysis performed by Zverkov and Jacobs (2020).

[6] Acamptonectes densus Mollesaurus periallus Ophthalmosaurus natans Ophthalmosaurus icenicus Gengasaurus nicosiai Nannopterygius yasykovi Nannopterygius enthekiodon Nannopterygius saveljeviensis Nannopterygius borealis Arthropterygius volgensis Arthropterygius lundi Arthropterygius thalassonotus Arthropterygius hoybergeti Arthropterygius chrisorum Brachypterygius extremus Aegirosaurus leptospondylus Muiscasaurus catheti Leninia stellans Sveltonectes insolitus Athabascasaurus bitumineus Platypterygius americanus Acuetzpalin carranzai Platypterygius sachicarum Caypullisaurus bonapartei Grendelius mordax Grendelius alekseevi Grendelius pseudoscythicus Grendelius zhuravlevi Undorosaurus kielanae Undorosaurus nessovi Undorosaurus gorodischensis Platypterygius australis Plutoniosaurus bedengensis Simbirskiasaurus birjukovi Platypterygius hercynicus Sisteronia seeleyi Platypterygius platydactylus Maiaspondylus lindoei