Jainosaurus (Jain's lizard) was a huge titanosaurid dinosaur of India and wider Asia, which lived in the Maastrichtian (approximately 68 mya). An herbivorous quadruped, an adult Jainosaurus would have measured around 18 m long and 6m high. No accurate estimate of the weight has yet been made.

The taxonomic rank of Jainosaurus is doubtful on many fronts. The first remains found were secret as Antarctosaurus septentrionalis by Friedrich von Huene and Matley in 1933, but in 1995 Hunt, Locley, Lucus & Meyer recognized them as forming a distinct genus. However, Jain himself (for whom the lizard is named) now believes that the remains stand for merely a young or female Titanosaurus and not a distinctive genus at all. It is unlikely that the matter will be determined soon as so few remains have been found - only a basicranium and partial postcranial.