Arnold Keith Alexander (June 12, 1921 – December 18, 1972) was a politician in Manitoba, Canada. He was a Progressive Conservative member of the Legislative Assembly of Manitoba from 1958 to 1966.
Born in Russell, Manitoba, Alexander was educated at the University of Manitoba. He served as a pilot in the Canadian Armed Forces from 1941 to 1954. After retiring from the armed forces, he farmed in the Tummel area of Manitoba until 1969. The following year, Alexander became a United Church minister.