Neill Smith Brown (April 18, 1810 – January 30, 1886) was an American politician and diplomat who served as Governor of Tennessee from 1847 to 1849, and as the United States Minister to Russia from 1850 to 1853. He also served several terms in the Tennessee House of Representatives, and was Speaker of the House for the 1855–1857 term. A lifelong Whig, Brown campaigned to keep Tennessee in the Union in the years leading up to the Civil War.