(January 18, 1806 – April 24, 1883) was an early leader in the Latter Day Saint movement. One of the original members of the Quorum of the Twelve Apostles, McLellin later broke with church founder Joseph Smith.
McLellin was born in Smith County, Tennessee, a son of Charles McLellin. He married for the first time on July 30, 1829, but his wife, Cynthia Ann McLellin, died young and he was a widower by 1832. McLellin married Emeline Miller on April 26, 1832 in Hiram, Ohio. Emeline was born September 4, 1809, in Pomfret, Vermont, to Martin Miller and Rebecca Jacobs. Emeline died November 1, 1907, in Grayson County, Texas. McLellin and Emeline were the parents of four sons and two daughters: Charles William, Sarah E., James Martin, Helen Rebecca, Albert Eugene, and Marcus Nelson.
McLellin first had contact with the missionaries of the Latter Day Saint Church of Christ in Paris, Tennessee, during 1831. He traveled to Missouri to further investigate the church, and was baptized on Aug 20, 1831and ordained an elder. During 1831, he also traveled with Hyrum Smith, and the two of them preached in Tennessee. McLellin then relocated to Kirtland, Ohio.
In 1832 and 1833, McLellin served a mission for the church, traveling with Parley P. Pratt. However, in a revelation to Joseph Smith on March 8, 1833, it was said that the Lord was «not pleased with my servant William E. McLellin».