William Augustus Elmore (October 13, 1812 – October 6, 1890) was a 19th-century lawyer and judge in New Orleans, Louisiana. Born in Laurens District, South Carolina to John Archer Elmore and Nancy Ann Martin; among his siblings was his half brother Franklin H. Elmore, who served in both U.S. House of Representatives and the U.S. Senate representing South Carolina. Elmore married twice, first to Mary Ann Morrison on July 28, 1840. Following her death, he married Julia Minor on January 2, 1851 in Ascension Parish. He had children by both wives.