The Holy Spirit Association for the Unification of World Christianity (also known as the Unification Church) is a modern religious movement. It was founded in South Korea in 1954 by Sun Myung Moon. In the next few decades it expanded to most nations of the world and now has five to seven million members.

Unification Church beliefs are based on the Bible and are explained in the church's textbook, Divine Principle. The Blessing ceremony of the Unification Church, a wedding or marriage rededication ceremony, is a church practice which has attracted wide public attention. The Unification Church has tried to engage in interfaith activities with other religions, including mainstream Christianity and Islam, despite theological differences.

The Unification Church sponsored many organizations and projects over the years; including businesses, news media, projects in education and the arts, and political and social activism. It has a megachurch in Seoul, Korea and the Peace Island in Liberia with the New Hope Academy situated there. "One Family Under God" is a phrase used by the church and the legal trademark of some of its affiliates. The church leadership has been by Moon and his wife, Hak Ja Han, who are expected to pass it on to their children.

Hak Ja Han (Korean: 한학자, Hanja: 韓鶴子) or Hakja Han Moon (born January 6, 1943 in Korea) is an influential member of the Unification Church and the wife of the church's founder, Sun Myung Moon. They married in April 1960 and have 13 children and 20 grandchildren. They are viewed by Unification Church members as the "new messiahs," and are referred to as the "True Parents"; she is called the "True Mother" and regarded as the "perfect woman".

In 1992 she established the Unification Church affiliated-organization Women's Federation for World Peace, and traveled the world speaking on its behalf. Han's influence within the Unification Church has steadily increased. She is Moon's designated successor as the leader of the Unification Movement. In the American media Han is sometimes referred to as "Mrs. Moon"; although in Korean culture a married woman keeps her original family name, with the children taking their father's.

Han, the daughter of a Korean woman who later became a follower of Sun Myung Moon, was born on January 6, 1943. Han attended an all-girls high school in Korea but did not go on to college. She speaks Japanese and English as well as Korean, although she speaks English with a Korean accent. In April 1960 at the age of 17, Han, by then a member of the Unification Church (which was officially founded in 1954), married Moon who was then 40 years old. Han has 13 children, and as of 1993 had 20 grandchildren.

Sun Myung Moon (Korean 문선명; born Mun Yong-myeong; 25 February 1920) is a South Korean billionaire, author, power broker, media mogul, peace activist, religious leader and founder of the Unification Church. The church has five to seven million members worldwide and often garners media attention for the blessing ceremony, a mass wedding or marriage rededication ceremony that can feature sometimes thousands of participants. The church's portfolio of global interests has become a multi-billion-dollar empire. The holdings include the UPI, The Washington Times, and the Tongil Group, a one of the largest South Korean business group or chaebol with business interests world-wide. The church is the largest owner of U.S. sushi restaurants and in the Kodiak region of Alaska, it is the area's largest employer. The church owns the only automobile manufacturing plant in North Korea, Pyeonghwa Motors, and is the second largest exporter of Korean goods. Three of Moon's NGOs, Universal Peace Federation, Women's Federation for World Peace and Service for Peace, are in consultative status with the United Nations Economic and Social Council.