The Seventh-day Adventist Church is an Adventist Protestant Christian denomination which is distinguished by its observance of Saturday, the seventh day of the week in the Christian (Gregorian) and the Hebrew calendar, as the Sabbath, its emphasis on the imminent Second Coming (advent) of Jesus Christ, and its annihilationist soteriology. The denomination grew out of the Millerite movement in the United States during the mid-19th century and it was formally established in 1863. Among its co-founders was Ellen G. White, whose extensive writings are still held in high regard by the church.

Much of the theology of the Seventh-day Adventist Church corresponds to common evangelical Christian teachings, such as the Trinity and the infallibility of Scripture. Distinctive post-tribulation teachings include the unconscious state of the dead and the doctrine of an investigative judgment. The church places an emphasis on diet and health, including adhering to Kosher food laws, advocating vegetarianism, and its holistic view of human nature—i.e. that the body, soul, and spirit form one inseparable entity. The Church holds the belief that "God created the universe, and in a recent six-day creation made the heavens and the earth, the sea, and all that is in them, and rested on the seventh day". Marriage is defined as a lifelong union between a man and a woman. The second coming of Christ, and resurrection of the dead, are among official beliefs.

The world church is governed by a General Conference of Seventh-day Adventists, with smaller regions administered by divisions, unions, local conferences and local missions. The Seventh-day Adventist Church is currently "one of the fastest-growing and most widespread churches worldwide", with a worldwide baptized membership of over 21 million people, and 25 million adherents. As of May 2007, it was the twelfth-largest religious body in the world, and the sixth-largest highly international religious body. It is ethnically and culturally diverse, and maintains a missionary presence in over 215 countries and territories. The church operates over 7,500 schools including over 100 post-secondary institutions, numerous hospitals, and publishing houses worldwide, a humanitarian aid organization known as the Adventist Development and Relief Agency (ADRA) and tax-exempt businesses such as Sanitarium which fund the church's charitable and religious activities.