John Whitmer was an early leader in the Latter Day Saint movement. He was one of the Eight Witnesses of the Book of Mormon's golden plates. Whitmer was also the first official Church Historian and a member of the presidency of the church in Missouri from 1834 to 1838.

The Eight Witnesses were one of the two groups of witnesses who made statements stating that they had seen the golden plates which Joseph Smith said was his source material for the Book of Mormon. An earlier group of witnesses who said they had seen the plates were called the Three Witnesses.