LeRoy Percy (November 9, 1860 – December 24, 1929) was an American attorney, planter, and Democratic politician who served as a United States Senator from the state of Mississippi from 1910 to 1913.

Percy was a grandson of Charles "Don Carlos" Percy. He graduated from the University of the South at Sewanee in 1879, and the University of Virginia School of Law in 1881, where he was a member of the Chi Phi fraternity. He was admitted to the bar later that year and achieved wealth as an attorney. Often being paid in land, he became a major planter in Greenville, Mississippi, in the heart of the Mississippi Delta. His plantation of Trail Lake eventually covered 20,000 acres and was worked by black sharecroppers and Italian immigrants. He also leased land in Chicot County in the Arkansas Delta.

Percy's influence led him to become active in politics. He was elected by the state legislature to the U.S. Senate in 1910. In 1912, he was defeated in the first popular election of a U.S. Senator in the state, by the populist James K. Vardaman, a white supremacist, who attacked Percy for being relatively liberal on race issues and for being a member of the state's planter elite. Vardaman, also a Democrat, ran unopposed in the general election.

In 1922, Percy came to national notice by confronting Ku Klux Klan organizers in Greenville and uniting local people against them. During the Great Mississippi Flood of 1927, Percy appointed his son, William Alexander Percy, to direct the work of thousands of black laborers on the levees near Greenville.^{[citation needed]}

Percy became an attorney in Greenville, Mississippi, the county seat of Washington County, Mississippi, in the Mississippi Delta. In his early years, some clients paid in horses and others in land, and Percy acquired a total of 20,000 acres. His plantation, Trail Lake, was worked by Black sharecroppers, who provided most of the labor on all of the plantations in the area and had been the majority of the population in the county since before the American Civil War. Percy gave them a better share than many others by setting up schools on the property for the children and allowing his tenants to buy land. He worked to build a community on the plantation.

Soon after starting his law practice, Percy married Camille, a French Catholic woman. They had two sons, of whom only one survived to adulthood, William Alexander Percy (1885–1942).

William followed his father into law. He served with distinction in World War I and was best known for his memoir, Lanterns on the Levee: Recollections of a Planter's Son, but also published poetry. Never married, William Percy took in and adopted his cousin's three sons when they were orphaned as boys (after their father's suicide and their mother's death in a car accident). The boys included Walker Percy, who became a notable novelist and won the National Book Award for his first book, The Moviegoer.

Percy also had interests in other plantations, such as by leasing Sunnyside Plantation in Chicot County, Arkansas, on the other side of the Mississippi River. Short on labor, the county recruited Italian immigrants in 1895 to work as sharecroppers. They found the conditions so unfavorable that most moved away to northwestern Arkansas. Others stayed but felt trapped by the sharecropper system of accounting, which seemed to be perpetual debt. They complained to their consulate.