The following lists events that happened during 1909 in the Commonwealth of Australia.

• Monarch – Edward VII
• Governor-General – William Ward, 2nd Earl of Dudley
• Prime Minister – Andrew Fisher (until 2 June), then Alfred Deakin
• Chief Justice – Samuel Griffith

• 8 January – Sir Thomas Bent retires as Premier of Victoria, and is replaced by John Murray.
• 9 March – Electric trams begin operation in Adelaide.
• 31 March – Victoria is the last Australian state to grant women's suffrage.
• 30 April – Tasmania begins to use the Hare-Clark single transferable vote method in the 1909 general election.
• 26 May – The Protectionist Party and the Free Trade Party merge to form the Fusion Party, led by Alfred Deakin.
• 2 June – The Labor government of Andrew Fisher is ousted from office by Alfred Deakin's Fusion Party, and Deakin becomes Prime Minister for the third time.
• 5 June – Steam trams begin operation in Rockhampton, Queensland.
• 18 to 21 August – Disastrous floods strike Victoria.
• 6 October – Martha Rendell becomes the last woman to be hanged in Western Australia.
• 9 October – John Earle becomes Premier of Tasmania, leading Tasmania's first Labor government, however Earle's minority government only lasts a week.
• 6 December - the Newcastle–Bolgart Railway was opened.
• 10 December – The University of Queensland is established.
• 14 December – New South Wales passes law ceding land to the Commonwealth for construction of the national capital, Canberra.
• 21 December – British Field Marshal Lord Kitchener arrives in Darwin after an invitation from Alfred Deakin to review Australia's military and defence plans.
• 24 December – Former Prime Minister Sir George Reid resigns from Parliament to become Australia's first High Commissioner to the United Kingdom.

• 16 July – The first powered aeroplane flight in Australia is made.

• 29 January – New South Wales wins the Sheffield Shield
• 15 June – Representatives from England, Australia and South Africa meet at Lord's and form the Imperial Cricket Conference.
• 21 August – Andrew Wood wins the inaugural men's national marathon title, clocking 2:59:15 in Brisbane. Though billed as the Australasian Championships, the Australian Athletic Union did not consider it to be the official championship.
• 31 August – The first interstate ice hockey competition is held in Melbourne.
• 14 September - The 1909 NSWRFL season culminates in the grand final which was forfeited by Balmain to make South Sydney back-to-back premiers
• 29 October – The South Melbourne Swans defeat the Carlton Blues 4.14 (38) to 4.12 (36) in the 1909 VFL Grand Final.
• 2 November – Prince Foote wins the Melbourne Cup.

• 19 January – Leon Goldsworthy, explosives expert (died 1994)
• 8 February – Elisabeth Murdoch, philanthropist (died 2012)
• 13 February – Reginald Ansett, businessman and aviator (died 1981)
• 2 March – Percival Bazeley, scientist (died 1991)
• 19 March – Nell Hall Hopman, tennis player (died 1968)
• 26 March – Chips Rafferty, actor (died 1971)^[1]
• 9 April – Robert Helpmann, dancer and choreographer (died 1986)
• 23 May – William Sidney, 1st Viscount De L'Isle, Governor General of Australia (died 1991)
• 15 June – Cyril Walsh, High Court judge (died 1973)
• 20 June – Errol Flynn, Australian actor (died 1959)
• 23 June – Keith Virtue, aviator (died 1980)
• 6 July – Eric Reece, Premier of Tasmania (died 1999)
• 9 September – Decima Norman, athlete (died 1983)
• 10 September – Dorothy Hill, geologist (died 1998)
• 3 December – Stanley Burbury, Governor of Tasmania (died 1995)

• 9 February – Charles Conder, artist (born and died in the United Kingdom) (b. 1868)
• 4 March – Max Hirsch, Victorian politician, businessman and economist (born in Prussia and died in Russia) (b. 1852)
• 14 March – William Charles Kernot, engineer (born in the United Kingdom) (b. 1845)
• 6 April – Sir Julian Salomons, 5th Chief Justice of New South Wales (born in the United Kingdom) (b. 1835)
• 18 April – William Saumarez Smith, Anglican archbishop (born in the United Kingdom) (b. 1836)
• 28 April – Henry D'Esterre Taylor, banker and federationist (b. 1853)
• 23 May – Elias Solomon, Western Australian politician (born in the United Kingdom) (b. 1839)
• 31 May – Thomas Price, 24th Premier of South Australia (born in the United Kingdom) (b. 1852)
• 29 June – Sir George Shenton, Western Australian politician (died in the United Kingdom) (b. 1842)
• 4 July – Alfred Compigne, Queensland politician (born in the United Kingdom) (b. 1818)
• 23 July – Sir Frederick Holder, 19th Premier of South Australia (b. 1850)
• 8 August – Mary MacKillop, religious sister (b. 1842)
• 18 September – Mary Lee, suffragette and social reformer (born in Ireland) (b. 1821)
• 6 October – Martha Rendell, convicted murderer (b. 1871)
• 10 November – George Essex Evans, poet (born in the United Kingdom) (b. 1863)
• 6 December – Sir William Henry Bundey, South Australian politician and judge (born in the United Kingdom) (b. 1838)