Ian James Watt AC (born 18 June 1950) is an Australian retired public servant, best known for his time as Secretary of the Department of the Prime Minister and Cabinet from September 2011 to November 2014.

[3] He was educated at La Trobe University and joined the Australian Public Service in 1971 in the Victorian Division of the Post Master General's Department.

On his return to Australia, Watt was appointed First Assistant Secretary of the Economic Division, Department of the Prime Minister and Cabinet, from March 1994 to November 1996; and was Deputy Secretary of the Department of the Prime Minister and Cabinet (DPM&C) and Executive Coordinator of the Economic, Industry and Resources Policy Group until March 2001.

[12] Watt is the former chair of the Organisation for Economic Co-operation and Development's (OECD's) Working Party of Senior Budget Officials.

[2] His appointments since resigning from the public service include directorships with the Grattan Institute and Citigroup Pty Limited.