The Church of Scientology International (CSI) is a California 501(c)(3) non-profit corporation. Within the worldwide network of Scientology corporations and entities, CSI is officially referred to as the "mother church" of the Church of Scientology.

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.