The type species, Lirainosaurus astibiae, was described by Sanz, Powell, Le Loeuff, Martinez, and Pereda-Suberbiola in 1999.

The combination of characters present in the new axial remains described, supports the placement of Lirainosaurus as a derived lithostrotian titanosaur closely related to the Saltasaurinae.

The results of an unpublished SVPCA abstract published in 2016 narrow down the exact position of Lirainosaurus by placing it as closer to Alamosaurus and Opisthocoelicaudia than to Saltasaurus.

Other contemporary dinosaurs in the Bellevue layer include the titanosaur sauropod Ampelosaurus, the rhabdodontid Rhabdodon and indeterminate ankylosaur and Dromaeosauridae elements.

However, the local stratigraphy presents the same succession of facies as in the Aix-en-Provence Basin, which is also in the Late Campanian to Early Maastrichtian age.