The Church of Satan (CoS) is a religious organization dedicated to the religion of Satanism as defined by Anton Szandor LaVey. Founded in San Francisco in 1966, by LaVey, it is considered the "oldest satanic religion in continual existence", and more importantly the most influential, inspiring "numerous imitator and breakaway groups". According to the Church, Satanism has been "codified" as "a religion and philosophy" by LaVey and his church. Founded in an era when there was much public interest in the occult, witchcraft and Satanism, the church enjoyed a heyday for several years after its founding. Celebrities attended LaVey's satanic parties and he was invited on talk shows. His Satanic Bible sold nearly a million copies.

LaVeyan Satanism is the name given to the form of Satanism promoted by American occultist and author Anton LaVey (1930–1997). LaVey founded the Church of Satan (CoS) in 1966 in San Francisco. Although LaVey is thought to have had more impact with his Satanic aesthetics of "colourful" rituals and "scandalous" clothes that created a "gigantic media circus", he also promoted his ideas in writings, such as the popular Satanic Bible. LaVeyan Satanism has been classified as a new religious movement and a form of Western esotericism by scholars of religion. LaVey's ideas have been said to weave together an array of sometimes "contradictory" "thinkers and tropes", combining "humanism, hedonism, aspects of pop psychology and the human potential movement", along with "a lot of showmanship", His ideas were heavily influenced by the ideas and writings of Friedrich Nietzsche, Ayn Rand and Arthur Desmond.