Murdo MacKenzie (April 24, 1850 – May 30, 1939) was twice (1891–1901 and 1922–1937) manager of the Scots-owned Matador Land and Cattle Company, and founding president of the American Stock Growers Association, for whom he testified before congress and the Interstate Commerce Commission. His testimony led to passage of the Hepburn Act of 1906 which eased railroad fares for western shippers.
President Teddy Roosevelt appointed him to the National Conservation Commission in 1908, and it was Mackenzie, then manager of the Brazil Land, Cattle and Packing Company, with whom Roosevelt stayed when he visited Brazil in 1913.