Amanzia (after Swiss geologist Amanz Gressly) is a genus of turiasaurian sauropod dinosaur from the Reuchenette Formation in Moutier, Switzerland.

Due to being found in association with the theropod tooth MH 350 found near Moutier that probably belonged to Ceratosaurus or an indeterminate member of the Ceratosauria, they were misidentified as belonging to a predatory dinosaur, for which Greppin in 1870 coined the name "Megalosaurus meriani" (named after Peter Merian).

However, in 1922, Janensch realized the vertebrae belonged to a sauropod, so he wrote to Friedrich von Huene, who gave them the name Ornithopsis greppini.

[8] In 2020, Daniela Schwarz, Philip D. Mannion, Oliver Wings and Christian A. Meyer gave it the genus name Amanzia, after Swiss geologist Amanz Gressly, who was the first to discover dinosaur bones in Switzerland.

[1] In 2020, no lectotype was selected, the naming authors maintaining the original syntype series indicated by von Huene, consisting of forty-nine bones.