The following lists events that happened during 1900 in Australia.
Governors of the Australian coloniesEdit
- Governor of New South Wales – William Lygon, 7th Earl Beauchamp
- Governor of Queensland – Charles Cochrane-Baillie, 2nd Baron Lamington
- Governor of South Australia – Hallam Tennyson, 2nd Baron Tennyson
- Governor of Tasmania – Jenico Preston, 14th Viscount Gormanston (until 14 August)
- Governor of Victoria – Thomas Brassey, 1st Earl Brassey (until 31 March)
- Premier of New South Wales – William Lyne
- Premier of South Australia – Frederick Holder
- Premier of Queensland – Robert Philp
- Premier of Tasmania – Elliott Lewis
- Premier of Western Australia – John Forrest
- Premier of Victoria – Allan McLean (until 19 November), then George Turner
- 3 January – Electric lighting is installed on Adelaide streets.
- 25 January – State Labour politicians meet in Sydney to formally found the federal Labour party.
- 25 March – The S.S. Glenelg is wrecked off the Victorian coast, resulting in 31 deaths.
- March to May – Record rainfall and flooding affect the Pilbara and Gascoyne regions of Western Australia
- 9 May – The Sierra Nevada is wrecked off Portsea, Victoria; 23 lives are lost.
- 2 July – Snow falls to extremely low levels in New South Wales, being recorded as low as Forbes.
- 5 July – The Commonwealth of Australia Constitution Act (UK) is passed.
- 24 July – Neville Howse rescues a fallen ally under heavy fire during the Second Boer War, becoming the first Australian recipient of the Victoria Cross.
- 8 August – The first Australian contingents of naval volunteers set sail for China to assist British and international troops during the Boxer Rebellion.
- 17 October – Natural gas is found at Roma in Queensland
- 27 October – Notorious murderer Jimmy Governor is apprehended near Wingham, New South Wales.
- 15 December – Upon his arrival in Australia, the first Governor-General, Lord Hopetoun, commits the so-called Hopetoun Blunder.
- 8 January – Merlyn Myer, Australian philanthropist (d. 1982)
- 25 January – Harold Raggatt, public servant (died 1968)
- 29 March – John McEwen, caretaker Prime Minister (1967–1968) (died 1980)
- 9 October – Frank O'Grady, Australian public servant (d. 1981)
- 19 October – Bill Ponsford, cricketer (died 1991)
- 20 October – Jack Lindsay, writer (died 1990)
- 3 December – Albert Hawke, Premier of Western Australia (1953–1959) (died 1989)
- About 4, 000, 000