How are Australian senators elected to the Parliament?

Australian senators are elected to Parliament by single transferable vote (STV), a form of proportional representation that elects multiple senators from each state or territory. Voters number candidates or parties in order of preference on the ballot paper, and seats are allocated according to quotas calculated from the total valid vote.

Senate elections work on a state-by-state basis. At a normal half-Senate election, each state elects six senators (half of the 12 it returns over a full six-year cycle). At a double dissolution, all 12 senators from each state are elected at once. The Australian Capital Territory and the Northern Territory each elect their two senators at every federal election. The quota for election is calculated as the total valid vote in the state divided by the number of seats plus one, plus one vote.

Voters can vote 'above the line' (numbering at least six party boxes in order of preference) or 'below the line' (numbering at least 12 individual candidates in order of preference). The 2016 Commonwealth Electoral Amendment Act abolished group voting tickets, which had previously allowed parties to direct preferences to obscure micro-parties, and required voters to express their own preferences. This reform was supported by the Greens and the Coalition and opposed by Labor and the Australian Democrats.

The proportional system has produced a Senate with substantial representation for minor parties and independents. As of 2026, the Senate typically includes Labor, Liberal, National, Green, One Nation, Lambie Network, United Australia Party, and independent senators alongside other minor party representatives. No federal government has held a Senate majority since 2007, requiring governments to negotiate with crossbench senators to pass legislation. The Senate's role in reviewing and amending government legislation has become a defining feature of Australian politics.