Lusotitan is a genus of herbivorous brachiosaurid sauropod dinosaur from the Late Jurassic of Portugal and possibly Spain.

In 1947 Manuel de Matos, a member of the Geological Survey of Portugal, discovered large sauropod fossils in the Portuguese Lourinhã Formation that date back to the Tithonian stage of the Late Jurassic period.

[3] In 2017, Mocho, Royo-Torres and Ortega suggested that Galvesaurus or Galveosaurus from the Late Jurassic of Spain might represent a junior synonym of this taxon.

[4] However, a 2019 description of new material of Galvesaurus by Perez-Pueyo et al. identified phylogenetically informative characters to distinguish it from Lusotitan which was recovered as its sister taxon.

Lusotitan lived alongside species of the predatory theropods Allosaurus (A. europaeus), Ceratosaurus, Lourinhanosaurus, and Torvosaurus, the ankylosaurian Dracopelta, the sauropods Bothriospondylus, Lourinhasaurus, and Zby, and the stegosaurs Dacentrurus and Miragaia.