The term mythology can refer either to a collection of myths (a mythos, e.g., Inca mythology) or to the study of myths (e.g., comparative mythology).

A mythology, in the sense of a collection of myths, is an important feature of many cultures. According to Alan Dundes, a myth is a sacred narrative explaining how the world and humankind assumed their present form, although, in a very broad sense, the word can refer to any traditional story. Bruce Lincoln defines myth as "ideology in narrative form". Myths may arise as either truthful depictions or overelaborated accounts of historical events, as allegory for or personification of natural phenomena, or as an explanation of ritual. They are used to convey religious or idealized experience, to establish behavioral models, and to teach. Modern mythopoeia such as fantasy novels, manga, and urban legend, with many competing artificial mythoi acknowledged as fiction, supports the idea of myth as a modern, not just ancient, social practice.

Mythology, in the sense of the study of myths, dates back to antiquity. Early rival classifications of Greek mythos by Euhemerus, Plato's Phaedrus, and Sallustius were developed by the neoplatonists and revived by Renaissance mythographers. Nineteenth-century comparative mythology reinterpreted myth as a primitive and failed counterpart of science (E. B. Tylor), a "disease of language" (Max Müller), or a misinterpretation of magical ritual (James Frazer). By contrast, many later interpretations have rejected a conflict between myth and science, sometimes viewing myths as expressions of, or metaphors for, human psychology. Tension between the search for a monomyth or Ur-myth and skepticism toward such comparativism has marked scholarship on myth.