Thomas Louis Sloan (14 May 1863– 10 September 1940) was a Native American lawyer and activist. Sloan worked alongside his partner, Hiram Chase, for much of his career. Sloan has a history of activism dating back to his teenage years. In 1911, he helped found the Society of American Indians. In addition, he established the first Indian-owned law office in Washington D.C. in 1912. Sloan was an activist for the citizenship of all Native Americans.