William A. Harris (October 29, 1841 - December 20, 1909) was a United States Representative and Senator from Kansas. Born near Luray, Virginia, he attended the common schools and graduated from Columbian College (later George Washington University), Washington, D.C., in 1859 and from the Virginia Military Institute at Lexington in 1861. During the Civil War he served three years in the Confederate Army, becoming adjutant general, and later ordnance officer in the Army of Northern Virginia. He moved to Kansas in 1865 and was employed as a civil engineer in the construction of the Union Pacific Railroad until 1868; that year, he moved to Lawrence, Kansas. He was appointed agent for the railroad companies in the sale of the Delaware Reservation and other lands, and in 1884 moved to Linwood, Leavenworth County and engaged in agricultural pursuits and stock raising.
Harris was elected as a Populist to the Fifty-third Congress (March 4, 1893-March 3, 1895) and was an unsuccessful candidate for reelection in 1894. He was a member of the Kansas Senate in 1895 and 1896, and was elected as a Populist to the U.S. Senate and served from March 4, 1897, to March 3, 1903. He was an unsuccessful candidate for reelection, and resumed his agricultural pursuits. He was an unsuccessful candidate for Governor of Kansas in 1906. Harris died in Chicago, where he had gone to work with the National Livestock Association, in 1909; interment was in Oak Hill Cemetery, Lawrence, Kansas.
William Alexander Harris was the son of William Alexander Harris (1805-1864), a U.S. Representative from Virginia.