The Seventh-day Adventist Church pioneers were members of Seventh-day Adventist Church, part of the group of Millerites, who came together after the Great Disappointment across the United States and formed the Seventh-day Adventist Church. In 1860, the pioneers of the fledgling movement settled on the name, Seventh-day Adventist, representative of the church's distinguishing beliefs. Three years later, on May 21, 1863, the General Conference of Seventh-day Adventists was formed and the movement became an official organization.

Hiram Edson (1806–1882) was a pioneer of the Seventh-day Adventist Church, known for introducing the sanctuary doctrine to the church. Hiram Edson was a Millerite adventist, and became a Sabbath-keeping Adventist. Like all Millerites, Edson expected that the Second Coming of Jesus Christ would occur on October 22, 1844. This belief was based on an interpretation of the 2300 day prophecy which predicted that "the sanctuary would be cleansed" which Millerites took to mean that Christ would return on that day.