List of Australian federal by-elections

This is a list of by-elections for the Australian House of Representatives from its creation in 1901 until the present day.

Casual vacancies in the House of Representatives arise when a member dies, is disqualified or resigns, or for some other reason the seat becomes vacant. Members normally resign by tendering resignation to the Speaker of the House of Representatives.

Casual vacancies are filled by by-elections. The Speaker has a discretion as to when to call a by-election and may not call one at all, for example, if a general election is imminent. At least 33 days must elapse between the issue by the Speaker of a writ and the date of a by-election, and the Speaker cannot issue the writ until receipt of a formal letter of resignation. A by-election must take place on a Saturday.

A supplementary election is held in an electorate following a scheduled general election if the election is not held.