Mordecai Baldwin Oliver (October 22, 1819 – April 25, 1898) was an attorney and two-term U.S. Representative from Missouri. Born in Anderson County, Kentucky, Oliver attended the common schools and then studied law.He was admitted to the bar in 1842 and commenced practice in Richmond, Missouri. He served as a prosecuting attorney for the Fifth Judicial Circuit in 1848. Oliver was elected as a Whig to the Thirty-third Congress and reelected as an Opposition Party candidate to the Thirty-fourth Congress (March 4, 1853–March 3, 1857).