The Parliament of Australia (officially the Federal Parliament, also called the Commonwealth Parliament) is the legislative branch of the government of Australia. It consists of three elements: the Crown (represented by the Governor-General), the Senate and the House of Representatives. The combination of two elected chambers, in which the members of the Senate represent the states and territories while the members of the House represent electoral divisions according to population, is modelled on the United States Congress. Through both chambers, however, there is a fused executive, drawn from the Westminster system.The upper house, the Senate, consists of 76 members: twelve for each state, and two each for the territories, Northern Territory (including Christmas Island and the Cocos (Keeling) Islands) and the Australian Capital Territory (including Norfolk Island and the Jervis Bay Territory). Senators are elected using the single transferable vote proportional representation system and as a result, the chamber features a multitude of parties vying for power. The governing party or coalition has not held a majority in the Senate since 1981 (except between 2005 and 2007) and usually needs to negotiate with other parties and Independents to get legislation passed.The lower house, the House of Representatives, currently consists of 151 members, each elected using full-preference instant-runoff voting from single-member constituencies known as electoral divisions (and commonly referred to as "electorates" or "seats"). This tends to lead to the chamber being dominated by two major political groups, the centre-right Coalition (consisting of the Liberal and National Parties) and the centre-left Labor Party. The government of the day must achieve the confidence of this House in order to gain and remain in power.

The House of Representatives has a maximum term of three years, although it can be dissolved early. The Senate has fixed terms, with 36 Senators' terms expiring every three years (the terms of the four territory Senators are linked to House elections). As a result, House and Senate elections almost always coincide. A deadlock-breaking mechanism known as a double dissolution can be used to dissolve the full Senate as well as the House in the event that the Senate refuses to pass a piece of legislation passed by the House.The two Houses meet in separate chambers of Parliament House (except in a rare joint sitting) on Capital Hill in Canberra, Australian Capital Territory.