(Greek: Ἑλληνισμός), the Hellenic ethnic religion (Ἑλληνικὴ εθνική θρησκεία), also known as Dodekatheism (Δωδεκαθεϊσμός), Olympianism, refers to various religious movements that revive ancient Greek religious practices, publicly, emerging since the 1990s.
Hellenic polytheists worship the ancient Greek Gods, including the Olympians, nature divinities, underworld deities (chthonic gods) and heroes. Both physical and spiritual ancestors are honored. It is primarily a devotional or votive religion, based on the exchange of gifts (offerings) for the gods' blessings. The ethical convictions of modern Hellenic polytheists are often inspired by ancient Greek virtues such as reciprocity, hospitality, self-control and moderation. The Delphic maxims, Tenets of Solon, the Golden Verses of Pythagoras, or even Aristotle's Ethics each function as complete moral codes that a Hellenic Polytheist may observe. Key to most ethical systems is the idea of kharis (or "charis", grace), to establish reciprocity between humanity and the gods, between individuals, and among community members. Another key value in Hellenic Polytheism is eusebeia, often translated as piety. This implies a commitment to the worship of the Hellenic gods and action to back this up.