Wapitisaurus is an extinct genus of thalattosaur from the Early Triassic. Its type and only species is Wapitisaurus problematicus. Its remains were discovered in the Vega-Phroso Member of the Sulphur Mountain Formation in British Columbia, Canada.
Wapitisaurus was originally described as a member of Weigeltisauridae, a family of gliding reptiles that otherwise is only known from the Permian period. However, subsequent study determined it was a member of Thalattosauria, a group of unusual marine reptiles that lived during the Triassic period. The length of Wapitisaurus has been estimated to be between 1mand1.9mm (03feetand06.2feetm), similar to other thalattosaurs.