David Alexander Nunn (July 26, 1833 – September 11, 1918) was an American politician and a member of the United States House of Representatives from Tennessee's 8th congressional district.
Nunn was born near Brownsville, Tennessee, in Haywood County. He attended private schools and West Tennessee College (now Union University at Jackson, Tennessee. He studied law and graduated from Cumberland University at Lebanon, Tennessee, in 1853. He was admitted to the bar, and he commenced practice in Brownsville.
He was a presidential elector on the Constitutional Union ticket in 1860 and on the Republican Ticket in 1864.
Nunn was elected as a Republican to the Fortieth Congress, but was an unsuccessful Independent Republican candidate for re-election in 1868 to the Forty-first Congress. He served from March 4, 1867 to March 4, 1869.
He was appointed Minister Resident to Ecuador on April 21, 1869, by President Grant. He resigned on November 2, 1869. He was elected to the Forty-third Congress, serving from March 4, 1873 to March 3, 1875. He was an unsuccessful candidate for re-election to the Forty-fourth Congress in 1874.
He was the secretary of state of Tennessee from 1881 to 1885. He was appointed by President McKinley as collector of internal revenue at Nashville, Tennessee on July 20, 1897. He served until his resignation on November 7, 1902. He returned to private life.
Nunn died in Brownsville, Tennessee, and was interred in Oakwood Cemetery.