1920 in Australia

Incumbents

• Monarch – George V
• Governor-General – Ronald Munro Ferguson, then Henry Forster
• Prime Minister – Billy Hughes
• Chief Justice – Adrian Knox

  State premiers

• Premier of New South Wales – William Holman, then John Storey
• Premier of Queensland – Ted Theodore
• Premier of South Australia – Archibald Peake, then Henry Barwell
• Premier of Tasmania – Walter Lee
• Premier of Victoria – Harry Lawson
• Premier of Western Australia – James Mitchell

  State governors

• Governor of New South Wales – Sir Walter Davidson
• Governor of Queensland – Sir Hamilton Goold-Adams, then Sir Matthew Nathan
• Governor of South Australia – Sir Henry Galway, then Sir William Weigall
• Governor of Tasmania – Sir Francis Newdegate, then Sir William Allardyce
• Governor of Victoria – Sir Arthur Stanley
• Governor of Western Australia – Sir William Ellison-Macartney

  Events

• 22 January – The national Country Party of Australia is formed.
• 20 March – A state election is held in New South Wales. The Labor Party led by John Storey defeats the incumbent Nationalist Party.
• 2 April – Edward, Prince of Wales arrives in the country to thank Australians for the part they played in World War I.
• 22 April – The High Court of Australia rules in the case of R v Licensing Court of Brisbane; Ex parte Daniell, that simultaneous obedience was impossible in cases where federal and state law were inconsistent, and that according to the Constitution of Australia, in such cases the state law is invalid.
• 1 June – Adelaide has its wettest June day on record from a vigorous cold front with 53.6 millimetres setting the scene for the wettest winter on record in the Murray–Darling basin and second-wettest for all of southern Australia.
• 10 June – Perth has its highest daily rainfall until 1992 with 99.1 millimetres from a vigorous cold front
• 10 August – The Princes Highway is officially opened.
• 31 August – The High Court of Australia rules in the case of Amalgamated Society of Engineers v. Adelaide Steamship Co. Ltd., commonly known as the "Engineers' Case", that decisions of the Commonwealth Conciliation and Arbitration Court were binding on State governments.
• 21 October – A state election is held in Victoria. Harry Lawson and the Nationalist Party retain power.
• 30 October – The Communist Party of Australia is founded in Sydney.
• 16 November – The Queensland and Northern Territory Aerial Service, later known as Qantas, is founded in Winton.
• 3 December – The first successful flight from Melbourne to Perth is completed.
• 17 December – The authority to issue currency notes is transferred from Treasury on the Australian Notes Board.

  Arts and Literature

Sport

• 28 January – The New South Wales cricket team wins the 1919-20 Sheffield Shield.
• 20 April to 12 September – Australia competes at the 1920 Summer Olympics in Antwerp, winning one bronze and two silver medals. It is the first time Australia has competed at the Olympics separately from New Zealand – the two nations had previously competed as a combined Australasia team.
• Mid-year the 1920 Great Britain Lions tour of Australasia sees the Great Britain national rugby league team play the Ashes series in Australia.
• 1 September – Balmain Tigers win the New South Wales Rugby Football League season 1920 by gaining a seven-point lead with three rounds left in the season.
• 25 September – Victorian Football League Richmond defeat Collingwood 7.10 to 5.5 to win the 1920 VFL grand final.
• 2 November – Poitrel wins the Melbourne Cup

  Births

• 26 February – Michael Pate, actor
• 16 March – Leo McKern, actor
• 26 March – Oriel Gray, dramatist and playwright
• 10 May – John Brack, painter
• 12 May – Douglas Scott, National Party senator
• 18 June – Rosemary Dobson, poet
• 20 July – Arthur Boyd, artist
• 30 September – Russell Walter Fox, author and SA Supreme Court judge
• 3 November – Kath Walker, poet and activist
• 16 November – Colin Thiele, author

  Deaths

• 4 January – Robert Etheridge, Junior, palaeontologist
• 7 January – Edmund Barton, first Prime Minister of Australia
• 6 April – Archibald Peake, Premier of South Australia
• 9 August – Samuel Griffith, Premier of Queensland
• 12 August – Louisa Lawson, writer and feminist
• 16 August – Henry Daglish, Premier of Western Australia
• 15 September – Thomas Ewing, politician
• 28 November – Alfred Conroy, politician
• 21 December – Claude Tozer, cricketer