Themis was a Titaness, the daughter of Uranus and Gaia and the second consort of Zeus (after Metis). She was originally, like her mother, an earth goddess, but later became more and more specialised until she became a goddess of order, being particularly associated with assemblies.

The Greek word themis means 'law', 'right', but both it and her own name may derive from a root the- meaning 'put', 'make fast', as in tithemi, 'to set', 'settle', 'determine'. Her name is certainly related to English 'theme' and 'thesis', and possibly also to 'doom': as Jane Harrison points out, Doomsday is Judgment Day.