Uni appears in the Etruscan text on the Pyrgi Tablets as the translation of the Phoenician goddess Astarte. Livy states (Book V, Ab Urbe Condita) that Juno was an Etruscan goddess of the Veientes, who was ceremonially adopted into the Roman pantheon when Veii was sacked in 396BC. This seems to refer to Uni. She also appears on the Liver of Piacenza.
With her husband Tinia and Menrva, she was part of a powerful triumvirate.
In the Etruscan tradition, it is Uni who grants access to immortality to the demigod Hercle (Greek Heracles, Latin Hercules) by offering her breast milk to him.