Elections in Australia take place periodically to elect the legislature of the Commonwealth of Australia, as well as for each Australian state and territory. Elections in all jurisdictions follow similar principles, though there are minor variations between them. The elections for the Australian Parliament are held under the federal electoral system, which is uniform throughout the country, and the elections for state and territory Parliaments are held under the electoral system of each state and territory.
Part IV of Chapter 1 of the Australian Constitution briefly deals with eligibility for voting and election to the federal Australian Parliament. It does not prescribe how elections should be conducted. Election campaigns and associated political advertisements have some regulation. Public funding of political parties and party registration was introduced in 1983.
Voting is almost entirely conducted by paper ballot and is compulsory for adults. The informal vote is not usually significant, but a donkey vote is more common. They may, however, have a deciding impact in marginal seats.
The Parliament of Australia consists of two chambers, the House of Representatives and the Senate. The House of Representatives has 150 members, elected for a maximum term of three years in single-member constituencies (each approximately equal in voters). Elections are conducted by a system of preferential voting (specifically, the alternative vote).
The Senate has 76 senators, elected through a preferential system of proportional representation with a system of single transferable vote, with each state constituting a single constituency normally returning 6 senators every three years and each territory constituting a single constituency returning two senators. Electors in the two territories elect senators for non-fixed terms that are defined by the term of the House of Representatives. State senators serve fixed six-year terms, except in the case of a double dissolution, with half of the seats in each State expiring every three years.