Mangarevan mythology comprises the legends, historical tales, and sayings of the ancient Mangarevan people. It is considered a variant of a more general Polynesian mythology, developing its own unique character for several centuries before the 1830s. The religion was officially suppressed in the 19th century, and ultimately abandoned by the natives in favor of Roman Catholicism. The Mangarevan term for god was Etua.

Mangareva, also known as the Mangarevan language, is a Polynesian language spoken in the Gambier Islands of French Polynesia by about 1600 people on the islands of Gambier and Mangareva. Speakers also have some bilingualism in Tahitian, in which there is a 50-68% lexical similarity. It is a member of the Marquesic subgroup, and as such is closely related to Hawaiian and to the languages of the Marquesas Islands.

The term "mythology" can refer either to the study of myths (e.g., comparative mythology), or to a body or collection of myths (a mythos, e.g., Inca mythology). In folkloristics, a myth is a sacred narrative usually explaining how the world or humankind came to be in its present form, although, in a very broad sense, the word can refer to any traditional story. Myths typically involve supernatural characters and are endorsed by rulers or priests. They may arise as overelaborated accounts of historical events, as allegory for or personification of natural phenomena, or as an explanation of ritual. They are transmitted to convey religious or idealized experience, to establish behavioral models, and to teach.

Early rival classifications of Greek mythos by Euhemerus, Plato's Phaedrus, and Sallustius were developed by the neoplatonists and revived by Renaissance mythographers as in the Theologia mythologica (1532). Nineteenth-century comparative mythology reinterpreted myth as evolution toward science (E. B. Tylor), "disease of language" (Max Müller), or misinterpretation of magical ritual (James Frazer). Later interpretations rejected opposition between myth and science, such as Jungian archetypes, Joseph Campbell's "metaphor of spiritual potentiality", or Lévi-Strauss's fixed mental architecture. Tension between Campbell's comparative search for monomyth or Ur-myth and anthropological mythologists' skepticism of universal origin has marked the 20th century. Further, modern mythopoeia such as fantasy novels, manga, and urban legend, with many competing artificial mythoi acknowledged as fiction, supports the idea of myth as ongoing social practice.