Sir Alan Stewart Watt CBE (13 April 1901 – 18 September 1988) was an Australian diplomat.

Born of Scottish heritage,[2] Watt attended Sydney Boys High School.

[3] A graduate of the Universities of Sydney and Oxford, he was a New South Wales Rhodes Scholar for 1921.

[1][7][8] Watt first joined the Commonwealth Public Service in the Department of External Affairs, in 1937.

[4] In 1950 he returned to Australia and was appointed Secretary to the Department and was instrumental in negotiation of the ANZUS and SEATO treaties.