Ancient Greek Gods
Greek gods on the Siphnian Treasury, Delphi, ca. 530 BC
The Greeks believed in many gods: they were polytheistic (PA-lee-thee-ISS-tick). It is impossible to say how many Greek gods there were, because different Greeks worshipped different gods. Certainly there were hundreds. The most famous of them, and the ones which the most people sacrificed to, were Zeus, Hera, Apollo, Artemis, Poseidon, Aphrodite, Athena, Demeter, Hermes, Ares, and Hades.
But there were many others: Asclepius, the god of medicine, Persephone, Demeter's daughter, Gaia the earth goddess, Hecate, and so forth.
In addition, every little village had its own gods. The local stream, an especially big tree, an oddly shaped rock, all were thought to have their own god inside them, who had to be worshipped or he or she would get mad. It was, as Keith Hopkins has said, "a world full of gods."
Greek people also worshipped foreign gods, if for some reason they thought this might help them somehow. The Egyptian goddess Isis was especially popular in Athens in the Hellenistic period, for instance. And many Hellenistic Greeks worshipped Astarte, too.
For the Greek myths (stories about the gods), click here.
To find out more about the Greek gods, check out these books from Amazon or from your library:
D'aulaire's Book of Greek Myths, by Edgar and Ingri D'Aulaire.
Greek Religion, by Walter Burkert (reprinted 1987). By a leading expert, for adults. He has sections on each of the Greek gods, and discusses their deeper meanings, and their function in Greek society.