The Seventh-day Adventist (abbreviated "Adventist" ) Church is a Protestant Christian denomination which is distinguished mainly by its observance of Saturday, the "seventh day" of the week, as the Sabbath. The denomination grew out of the Millerite movement in the United States during the middle part of the 19th century and was formally established in 1863. Among its founders was Ellen G. White, whose extensive writings are still held in high regard by the church today.

Much of the theology of the Seventh-day Adventist church corresponds to key evangelical teachings such as the Trinity and the infallibility of Scripture. Distinctive teachings include the unconscious state of the dead and the doctrine of an investigative judgment. The church is also known for its emphasis on diet and health, for its promotion of religious liberty, and for its culturally conservative principles.

The world church is governed by a General Conference, with smaller regions administered by divisions, union conferences and local conferences. It currently has a worldwide membership of over 15 million people, has a missionary presence in over 200 countries and territories and is ethnically and culturally diverse. The church operates numerous schools, hospitals and publishing houses worldwide, as well as a prominent humanitarian aid organization known as the Adventist Development and Relief Agency (ADRA).