The Church of Scientology is a group of interconnected corporate entities and other organizations devoted to the practice, administration and dissemination of Scientology, which is variously defined as a cult, a business, or a new religious movement. The movement has been the subject of a number of controversies, and the Church of Scientology has been described by government inquiries, international parliamentary bodies, scholars, law lords, and numerous superior court judgements as both a dangerous cult and a manipulative profit-making business. In 1979, several executives of the organization were convicted and imprisoned for multiple offenses by a U.S. Federal Court. The Church of Scientology itself was convicted of fraud by a French court in 2009, a decision upheld by the supreme Court of Cassation in 2013. The German government classifies Scientology as an unconstitutional sect. In France, it has been classified as a dangerous cult. In some countries, it has attained legal recognition as a religion.

Scientology is a set of beliefs and practices invented by the American author L. Ron Hubbard, and an associated movement. It is variously defined as a cult, a business, a religion, a scam, or a new religious movement. Hubbard initially developed a set of ideas that he called Dianetics, which he represented as a form of therapy. An organization that he established in 1950 to promote it went bankrupt, and Hubbard lost the rights to his book Dianetics in 1952. He then recharacterized his ideas as a religion, likely for tax purposes, and renamed them Scientology. By 1954, he had regained the rights to Dianetics and founded the Church of Scientology, which remains the largest organization promoting Scientology. There are practitioners independent of the Church, in what is referred to as the Free Zone. Estimates put the number of Scientologists at under 40,000 worldwide.