Delphi (; Greek: Δελφοί [ðelˈfi]), in legend previously called Pytho (Πυθώ), was an ancient sacred precinct and the seat of Pythia, the major oracle who was consulted about important decisions throughout the ancient classical world. The ancient Greeks considered the centre of the world to be in Delphi, marked by the stone monument known as the omphalos (navel).

According to the Suda, Delphi took its name from the Delphyne, the she-serpent (drakaina) who lived there and was killed by the god Apollo (in other accounts the serpent was the male serpent (drakon) Python).

The sacred precinct occupies a delineated region on the south-western slope of Mount Parnassus.

It is now an extensive archaeological site, and since 1938 a part of Parnassos National Park. The precinct is recognized by UNESCO as a World Heritage Site in having had a great influence in the ancient world, as evidenced by the various monuments built there by most of the important ancient Greek city-states, demonstrating their fundamental Hellenic unity.

Adjacent to the sacred precinct is a small modern town of the same name.