As Eupatridai (Greek Εὐπατρίδαι, Eupatridae, " of noble ancestors", " of good fathers ") of the Athenian aristocracy of birth was designated, equipped with special rights. The more that democracy was reflected in the Attic Constitution, the more these privileges were limited, however, so that their power founded only on their property and wealth.

With the collective name Eupatridai first Athenian nobles were named. The term refers not only to the lifestyle on the incidence and economic possibilities of the nobility, but also reflects explicitly the origin of the signified. The noble families were built patriarlineal and made no major clans. The role of Eupatridai in the Archaic period remains unclear, only since about the 3rd quarter of the 6th century BC a first evidence of the term comes from a grave stone from Eretria Other notices that refer to archaic times, are later constructs. It is possible, however, that certain privileges as in the occupation of the Areopagus, were present. It is also known that Eupatridai were involved in the fight against the tyranny of Hipparchus, especially in the assassination attempt against him. Since classical times, the prerogatives of the Eupatridai only symbolic in nature, such as Phylenkönig or certain priest offices, tangible. Outside of Athens the term is often used as a synonym for the term nobility, often as the equivalent of the Roman Latin patricius.

In Athens, there was also a noble family named Eupatridai.