The Unification Church of the United States is the branch of the Unification Church in the United States. It began in the late 1950s and early 1960s when missionaries from South Korea were sent to America by the international Unification Church's founder and leader Sun Myung Moon. It expanded in the 1970s and then became involved in controversy due to its theology, its political activism, and the lifestyle of its members. Since then, it has been involved in many areas of American society and has established businesses, news media, projects in education and the arts, as well as taking part in political and social activism, and has itself gone through substantial changes.

The Unification Church (Korean: 통일교) is a new religious movement, derived from Christianity, whose members are called Unificationists or sometimes informally Moonies. Sun Myung Moon (1920–2012) began gaining followers after the Second World War. On 1 May 1954 in Seoul, South Korea, Moon formally founded the Holy Spirit Association for the Unification of World Christianity (HSA-UWC), the Unification Church's full name until 1994, when it was officially changed to the Family Federation for World Peace and Unification. It has a presence in approximately 100 countries around the world. Its leaders are Moon and his wife Hak Ja Han, whom their followers honor with the title "True Parents".