Trigonosaurus is a genus of titanosaurian sauropod dinosaur from the Late Cretaceous Period of what is now Brazil. The type species, Trigonosaurus pricei, was first described by Campos, Kellner, Bertini, and Santucci in 2005. It is based on two specimens, both consisting mainly of vertebrae. Before its description, it was known as the "Peirópolis titanosaur", after the place it was found.