The Portezuelo Formation is a geologic formation of Late Cretaceous (Late Turonian to Early Coniacian) age, outcropping in the Mendoza, Río Negro and Neuquén provinces of Argentina.

Sandstones and siltstones, probably deposited under fluvial conditions, make up the Portezuelo Formation.

There are also occasional cemented claystone deposits, as well as numerous paleosols (fossil soils).

The formation varies between 95 and 130 metres (312 and 427 ft) thick throughout its range.

[2][4] Many dinosaur fossils have recently been described from this formation, as well as remains of several other types of animals: