Sektensaurus (meaning "island lizard", sekten meaning "island" in Tehuelche) is a genus of ornithopod dinosaur, possibly an elasmarian, from the Late Cretaceous (Campanian) of Patagonia, Argentina. Its remains were uncovered in the fluvial tuffs of the Lago Colhué Huapí Formation in the Golfo San Jorge Basin. The type and only species is S. sanjuanboscoi.
Sektensaurus is the first non-hadrosauroid ornithopod of central Patagonia. The discovery of the genus increases the anatomical knowledge of ornithopods and adds new data on the compositions of dinosaur faunas that lived in Patagonia close to Antarctica at the end of the Cretaceous.