Theodore M. Brantley (or Brantly[note 1]) (February 12, 1851 – September 16, 1922) was the longest-serving Chief Justice of the Montana Supreme Court, serving for 23 years (1899–1922).

He remained Chief Justice until resigning for reasons of health shortly before his death in 1922, in Helena, Montana.

[6] Neill Duncan Brantly (1897–1972) joined the navy and became a Rear Admiral during World War II, commanding vessels at the Battle of Leyte Gulf.

[7] Lois Brown Brantly (1894–1972) married Frank A. Hazelbaker, lieutenant governor of Montana 1929–1933.

Brantly Hall at the University of Montana is named after Brantley's wife Lois, who served as head resident there for many years.