The Seventh-day Adventist Church (SDA) 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.

Adventism is a branch of Protestant Christianity that believes in the imminent Second Coming of Jesus Christ. It originated in the 1830s in the United States during the Second Great Awakening when Baptist preacher William Miller first publicly shared his belief that the Second Coming would occur at some point between 1843 and 1844. His followers became known as Millerites. After Miller's prophecies failed, the Millerite movement split up and was continued by a number of groups that held different doctrines from one another. These groups, stemming from a common Millerite ancestor, collectively became known as the Adventist movement.