Duncan Spears Casper (December 8, 1824 – May 20, 1898) was an early Mormon pioneer and one of the first settlers of Holladay, Utah. Casper was in Bellville, Ohio, the son of William Casper and Avarilla Durbin. His mother joined the Campbellites when he was eight years old, and a year later, after Mormon missionaries came through their area, his older brother William Wallace Casper joined the Latter Day Saint Church of Christ. Casper's parents joined two years later and in 1837 they moved the family to Missouri, where they purchased a home.