Wicca ( /ˈwɪkə/) is a modern pagan religion that draws upon a diverse set of ancient pagan religious motifs for its theological structure and ritual practice. The religion usually incorporates the practice of witchcraft. Developed in England in the first half of the 20th century, Wicca was later popularised in the 1950s and early 1960s by Gerald Gardner. Gardner was a retired British civil servant, and an amateur anthropologist and historian who had a broad familiarity with pagan religions, esoteric societies and occultism in general. At the time Gardner called it the "witch cult" and "witchcraft", and referred to its adherents as "the Wica". From the 1960s onward, the name of the religion was normalised to "Wicca".

Wicca is traditionally and primarily a duotheistic religion centred upon the idea of gender polarity and the worship of a Moon Goddess and a Horned God. (This core theology was originally described by Gerald Gardner, the founder of the religion; and Doreen Valiente, who wrote much of the original liturgical materials.) The Goddess and the God may be regarded as the Divine Feminine and the Divine Masculine. They are complementary opposites or dualities, bearing similarities to the concept of yin and yang in Taoism. The God and Goddess are generally seen as lovers and equals, the Divine Couple who together co-create the cosmos. (See Wiccan views of divinity.)

In addition to the core duotheism of Wicca, however, there are several other theological positions possible, including pantheism, polytheism, and henotheism; and even, for Dianic feminist witches, a form of monothestic goddess worship. These various theological perspectives are not necessarily regarded as mutually exclusive, and any individual Wiccan may shift from one perspective to another, or combine two or more perspectives together in one ritual. The metaphysical flexibility that allows for embracing more than one theological perspective at a time may seem paradoxical, but it is a common feature of Wicca as a mystery religion.

Wicca also involves the ritual practice of magic, ranging from the "low magic" or "folk magic" of shamanism and witchcraft to more elaborate and complex rites influenced by the ceremonial magic of the Western Hermetic Tradition. Wiccans frequently subscribe to a broad code of morality known as the Wiccan Rede, although this is not taken literally or even adhered to by all Wiccans. Another characteristic of Wiccan religion is the ritual celebration of the lunar and solar cycles. Lunar rites, known as esbats are usually held around the time of the full moon; but they may also be held at the new moon, or the waxing or waning moon. The solar or seasonal festivals, known as sabbats take place eight times a year, in regular intervals known as the Wheel of the Year. While both the God and the Goddess are usually honoured at both kinds of rituals, the Goddess is mainly associated with the Moon, and the God is mainly associated with the Sun.

There are various denominations within Wicca, which are referred to as traditions. Some, such as Gardnerian and Alexandrian Wicca, follow in the initiatory lineage of Gardner. Others, such as the Dianic tradition, take primary influence from other figures and may not insist on any initiatory lineage.

The application of the word Wicca has given rise to "a great deal of disagreement and infighting". Gardnerian and Alexandrian Wicca are often collectively termed British Traditional Wicca, and many of their practitioners consider the term Wicca to apply only to these lineaged traditions. Others do not use the word "Wicca" at all, instead preferring to be referred to only as "Witchcraft," while others believe that all modern witchcraft traditions can be considered "Wiccan." Popular culture, as seen in TV programmes like Buffy the Vampire Slayer tends to use the terms “Wiccan” and "Wicca" as completely synonymous with the terms “Witch” and “Witchcraft” respectively.

Read more about Wicca:  Beliefs, Practices, Traditions, Acceptance of Wiccans, Debates Over The Origin of Wicca