Assistant to the Quorum of the Twelve Apostles, commonly shortened to Assistant to the Twelve or Assistant to the Twelve Apostles, was a priesthood calling in the Church of Jesus Christ of Latter-day Saints between 1941 and 1976. As the title of the calling suggests, men who held this position assisted the Quorum of the Twelve Apostles in fulfilling their priesthood responsibilities. Assistants to the Twelve were general authorities, and were generally assigned by the Twelve Apostles to preside over and speak at stake conferences; re-organize stakes; tour missions; and assist in the direction of worldwide missionary work. Like counselors in the First Presidency, Assistant to the Twelve was not a distinct priesthood office—rather, it was a calling that any worthy high priest could be asked to fill.

Lowell Tom Perry was an American businessman and religious leader who was a member of the Quorum of the Twelve Apostles of the Church of Jesus Christ of Latter-day Saints from 1974 until his death.