Isonomia ( gr ἰσονομία, by Ison, "equal", and némein, " distribute " ) called in ancient Greece the political equality of all full citizens of a polis. Accordingly, slaves, women and metics ( strangers ) were excluded from the isonomy.

The isonomy formed the basis of democracy in the ancient Greek city-states, but the ancient democracy can not be equated with the modern concept of democracy ( for instance due to the lack of separation of powers ). Approximately 508/507 BC in Athens, led by Cleisthenes reforms that were based on the isonomia ( " balance, equality " ) and isegoria ( " equal rights, equal freedom to speak "). Isonomia saw itself as opposed to the Eunomia ( " good order " ), the 594 BC introduced by Solon social order, and aimed primarily dependent on preventing the tyranny and the rule of aristocratic cliques. It now elections were held ( most officials but were chosen by lot ), just as officials were also sworn to represent the interests of citizens. The end point of this development eventually put the BC to the middle of the 5th century BC Athenian democracy established in Athens dar.

The idea of ​​isonomy was taken up in Europe during the Enlightenment again.