Horace Maynard (August 30, 1814 – May 3, 1882) was an American politician who served as attorney general of Tennessee, U.S. Representative in Congress and as U.S. Postmaster General in the Rutherford B. Hayes administration.
Born in Westborough, Massachusetts, he was educated in local common schools and graduated from Amherst College in 1838. He was then a professor at the East Tennessee University, now the University of Tennessee, from 1839 through 1844. After studying law and passing the bar he became a lawyer in Tennessee and shortly thereafter a politician. He was elected with the Whig, American, Opposition and Unionist Parties to the United States House of Representatives. He remained loyal to the Union when Tennessee seceded and remained in Congress until 1863.
During the last two years of the American Civil War, he served as Tennessee Attorney General. He attended the National Union Convention in 1866 and was elected to the 39th Congress as an Unconditional Unionist the same year following the readmission of Tennessee into the Union. He then served in the 40th, 41st, 42nd and 43rd Congresses as a Republican. During the 43rd Congress he acted as chairman of the U.S. House Committee on Banking and Currency.
He was also a presidential elector on the Whig ticket in 1852 and on the Republican ticket in 1864.
In 1874 he ran for Governor of Tennessee as a Republican, but lost to James D. Porter, Jr.. He was appointed Minister to Turkey and served from 1875 to 1880 in that post. He was appointed United States Postmaster General in the Cabinet of President Rutherford B. Hayes and served from June 2, 1880 to March 5, 1881. He died in Knoxville, Tennessee in 1882 and is buried in Old Gray Cemetery.