Andesaurus (/ˌændəˈsɔːrəs/ AN-də-SOR-əs; "Andes lizard") is a genus of basal titanosaurian sauropod dinosaur which existed during the middle of the Cretaceous Period in South America.

[1] Elements of the pelvis were also discovered, including two ischia and a pubis bone, along with rib fragments and an incomplete humerus and femur.

[2] The dorsal vertebrae of Andesaurus bear the typical features of an opisthocoelous centrum and large lateral pleurocoel (pneumatic depression).

Unlike related Phuwiangosaurus, there is no ventral keel under any of the vertebrae, and there is a pneumatic feature on the front of the neural arch, the latter being found in most neosauropods.

Potentially diagnostic for Andesaurus, there is an additional ridge supporting the lower articulation for the ribs (parapophysis), although poor preservation in other vertebrae means it can only be identified on one bone.

The first caudal has a flat anterior and slightly convex posterior face, different from the subsequent vertebrae similar to in Epachthosaurus.

Andesaurus itself is only characterized by a single feature, the tall neural spines on top of its back vertebrae, and needs further study.