Thomas Henry Carter (born October 30, 1854) was a Republican senator from the state of Montana who served in the United States Senate from December 2, 1889, to March 3, 1911. A historical member of Congress, he is associated with Montana’s early years of statehood and representation at the federal level. Over the course of his Senate service, Carter completed three terms in office.

Carter’s tenure in the Senate spanned more than two decades, from the late nineteenth century into the early twentieth century. Serving as a Republican senator for Montana, he participated in national legislative affairs during a period of significant political and economic change in the United States. He left office as a former senator in 1911, concluding a long career in federal legislative service.