Laplatasaurus (meaning "La Plata lizard", named for La Plata, Argentina) is a genus of titanosaurian sauropod dinosaur that lived during the Late Cretaceous in South America, with the holotype and only known specimen found in the Anacleto Formation.

[3] This last species is today commonly referred to the original Titanosaurus.Huene based Laplatasaurus on fragmentary material found in three locations in Argentina, in strata of the Anacleto Formation,[4] dating from the Campanian faunal stage.

Huene never assigned a holotype, but in 1979 José Fernando Bonaparte chose MLP 26-306 as the lectotype, a specimen consisting of a tibia and a fibula that perhaps originate from different individuals.

Osteoderms forming an armored plating on the back, have been referred to Laplatasaurus but the association is uncertain.

A Megaloolithus egg found in the Anacleto Formation in Auca Mahuevo, Argentina[5] that was once assigned to Titanosaurus may have instead been laid by Laplatasaurus.