Wicca (IPA: /ˈwɪkə/) is a pagan, nature-based religion popularised in 1954 by Gerald Gardner, a retired British civil servant, who at the time called it Witchcraft and its adherents "the Wica".[1] He said that the religion, of which he was an initiate, was a modern survival of an old witchcraft mystery religion which had existed in secret for hundreds of years, originating in the pre-Christian paganism of Europe.[1] The veracity of Gardner's statements cannot be independently proven, however, and it is possible that Wiccan theology began to be compiled no earlier than the 1920s.

Various Wiccan lineages or 'traditions' have since branched out of that popularised by Gardner, which came to be called Gardnerian Wicca. Each lineage has distinctive rituals, oral traditions and liturgy, and most remain secretive and require that members be initiated. Other traditions have also formed independently of Gardnerian lineage, including a growing movement of Eclectic Wiccans who do not believe that any doctrine or traditional initiation is necessary in order to practice Wicca.

The term 'Wicca' has somewhat different usage. Traditionally 'Wicca' referred only to initiatory witchcraft in the lineage of Gerald Gardner and the New Forest coven (e.g. Gardnerian and Alexandrian Wicca), sometimes referred to as British Traditional Wicca in North America. More recently the term 'Wicca' has become more inclusive and encompasses a number of traditions inspired by but independent of that lineage.