Nebulasaurus is an extinct genus of basal eusauropod dinosaur known from the early Middle Jurassic Zhanghe Formation of Yunnan Province, China. It is known only from the holotype braincase LDRC-v.d.1. A phylogenetic analysis found Nebulasaurus to be a sister taxon to Spinophorosaurus from the Middle Jurassic of Africa. This discovery is significant paleontologically because it represents a clade of basal eusauropods previously unknown from Asia.

Eusauropoda is a derived clade of sauropod dinosaurs. Eusauropods represent the node-based group that includes all descendant sauropods starting with the basal eusauropods of Shunosaurus, and possibly Barapasaurus, and Amygdalodon, but excluding Vulcanodon and Rhoetosaurus. The Eusauropoda was coined in 1995 by Paul Upchurch to create a monophyletic new taxonomic group that would include all sauropods, except for the vulcanodontids.