Quetecsaurus was first described and named by Bernardo González Riga, Leonardo Ortiz David in 2014 and the type species is Quetecsaurus rusconii. It is known solely from the holotype, a partial skeleton found in close association that includes a postorbital, teeth, the atlas, a rear cervical vertebra, an incomplete dorsal vertebra, a rear caudal centrum, dorsal ribs, a coracoid, five metacarpals and fragments of a humerus, radius and ulna. The holotype was collected from red mudstones of the Cerro Lisandro Formation, Neuquén Basin, dating to the middle or late Turonian stage of the Late Cretaceous. The specimen represents the first sauropod with well preserved materials from this formation.