Sir Alexander "Alec" James Downer (born February 9 1920) is an Australian politician. He was born in Adelaide, South Australia, into one of the state's oldest families (irreverently known as Old Adelaide Families or OAFs). He served as a Federal Member of Parliament from 1949-1964, and as the High Commissioner to the United Kingdom from 1967-1974.

Educated in Adelaide, Sir Alexander became interested in politics and began to investigate the possibility of following his Father into parliament. He was elected into Federal Parliament in 1949 as the Liberal member for Mayo, located in the southern suburbs of Adelaide.

Sir Alexander was elected leader of the opposition in 1954 and served in the same position for the next decade.

Sir Alec's son, Alexander Downer is also a high-profile MP who was opposition leader from 1994-1995 and is currently Federal Foreign Minister.