Big Brother (also known as Big Brother Australia) is an Australian reality show based on the international Big Brother format created by John de Mol Jr.. Following the premise of other versions of the format, the show features a group of contestants, known as "housemates" who live together in a specially constructed house that is isolated from the outside world. The housemates are continuously monitored during their stay in the house by live television cameras as well as personal audio microphones. Throughout the course of the competition, housemates are evicted from the house – eliminated from the competition. The last remaining housemate wins the competition and is awarded a cash prize. The series is named after the fictional totalitarian dictator from George Orwell's 1949 novel Nineteen Eighty-Four.
Big Brother was produced from 2001 and ran for eight seasons and a Celebrity Edition on Network Ten before the network cancelled it in July 2008 after experiencing audience erosion and controversy. Big Brother returned in 2012 on the Nine Network. Nine's iteration of the series lasted 3 seasons and was not renewed beyond 2015. Each of the first eleven previous seasons was produced by Endemol Australia and Endemol Southern Star.
In 2019, the Seven Network picked up the series, which was produced by Endemol Shine Australia. This iteration of the series was pre-recorded and featured a revamped competitive format, based on the American version of Big Brother and ran for four regular seasons (including a special edition featuring new and returning housemates in commemoration of the show's 21st anniversary in 2022) as well as a celebrity edition titled Big Brother VIP. As a result of a poor reception to the 15th season, a planned 16th season (and the fifth to be aired by Seven) that was announced for 2024 did not eventuate.
In November 2025, Big Brother returned to Network 10 for its sixteenth season, returning to the original live format with live nominations and evictions, with evictions decided by viewers and a 24/7 live stream, with Endemol Shine Australia continuing to produce. Big Brother has been confirmed to be returning in 2026 for its seventeenth season, to again air on Network 10.
Format
Housemates must remain in the house at all times, with the aim of avoiding eviction from the house to be the last Housemate remaining to win a substantial cash prize at the end of the series. Alternatively, housemates can also be removed from the house if Big Brother feels this is necessary and can voluntarily leave the show at any time. In order to support the housemates' well-being, all participants have access to psychologists and a doctor at all times. Housemates are filmed 24 hours per day with edited highlights broadcast during prime time slots every evening.
Big Brother While in the house, the housemates are under the watchful eye of Big Brother — the embodiment of the show's producers, who will act as an authoritative all-seeing voice of God to the housemates. Housemates are at all times under the control of Big Brother, a rule-enforcing authority figure who monitors the housemates' behaviour, sets tasks and punishments and provides the mechanism for contestants to make external requests. Unlike other versions of Big Brother, housemates would refer to Big Brother as if it was one person. Over the course of the series, Big Brother developed a dry wit in his interactions with the housemates. He would also offer to counsel his housemates in need of his wisdom.
Voice Executive producer Peter Abbott voiced Big Brother in seasons 1–3. Executive producer Nick Colquhoun provided the main voice of Big Brother in seasons 4–7, particularly during live nominations, eviction nights and other special shows, with Aaron Lucas and Rikkie Proost serving as the voice at other times during the show in the aforementioned seasons. Jonathan Coffey and Mark Grieve also voiced Big Brother in the early-mid seasons, and Amy Peel provided the female voice of Big Brother in season 7. Leon Murray provided the voice in the 2008 and 2012–2014 seasons. Chris Coucouvinis voiced Big Brother in the 2020–2023 seasons and Gold Coast-based voice artist Pete Cunningham provided the voice of Big Brother for the 2025 season.
In addition to the character of Big Brother, seasons 9–11 featured Surly the Pufferfish, who was voiced by the show's executive producer Alex Mavroidakis using a Cockney accent.
Eviction format
Over the duration of the competition, the housemates will face nominations and evictions to evict housemates from the house, eliminating them from the game. However, throughout the series, the format regarding evictions has changed.
Original format For Ten's and Nine's iterations of the series, the format of the show resembled the original Dutch version of the show - a format adapted by most versions of the Big Brother format. In this format, the competitive aspects are minimised. The eviction decisions were determined by viewer voting, housemates were not allowed to discuss nominations (at the risk of punishment) and most seasons did not feature any regular competitions for power or safety (except the Friday Night Games (seasons 5–8) and Showdowns (season 10) — where the winners were offered limited power to change the Nominations after voting).
The main elements of the original format are as follows:
Nominations: Every week, the housemates would participate in nominations, a secret voting process to determine who would be nominated for eviction that week. Each Housemate nominated two other fellow housemates in the Diary Room, providing full reasons to Big Brother for their nominations. The three or more housemates with the most nominations were nominated and faced Australia's vote For seasons 1–7 and the second half of season 8; each housemate had 3 nomination points to vote for two housemates — one housemate for two points, and another with one. For the first half of season 8; The power over nominations was given the viewers, with Australia voting to save a housemate via televoting and the 3 lowest vote receivers facing a House Eviction Vote. For seasons 9–11 and 16; each housemate had 5 nomination points to allocate to two housemates - For a 3/2 or 4/1 point allocation. Eviction: After the nominations are finalised, voting for viewers is open, with Australia voting to determine the evictee of that week. For seasons 1–5 and the second half of season 8; viewers voted to evict a nominee. The nominee with the most votes is evicted. For seasons 6 and 7; viewers had the option to both save and evict. Both vote tallies would be combined and the nominee with the highest net-evict vote (or lowest net-save vote), is evicted. For the first half of season 8; the housemates voted between Australia's nominees in a similar style to the original nomination vote (3 Eviction Votes to be allocated in a 2/1 vote allocation). The housemate with the most votes is evicted. For seasons 9–11 and 16; viewers voted to save a nominee. The nominee with the fewest votes is evicted. Finale: The final housemates would face a final vote to determine the winner of the series. For seasons 1–5; viewers voted to evict between the final 2 housemates. The housemate with the fewest votes is declared the winner. For seasons 6 and 7; viewers had the option to both vote to save and to evict between the final 2 housemates. Both vote tallies would be combined and the housemates with the highest net-save vote (or lowest net-evict vote), is declared the winner. For season 8; viewers voted to evict between the final 3 housemates. The housemate with the fewest votes is declared the winner. For seasons 9–11; final voting began with the final 5 or 6 housemates with Australia voting to win. Throughout the final week, the housemates with the lowest vote total are progressively evicted until 3 remain for the grand finale. Of the final 3, the finalist with the most votes to win is declared the winner. For season 16, final voting began with the final 5 Australia voting to win. The finalist with the most votes to win is declared the winner. Voting Method: Australia voted throughout the show by the following methods The first 8 seasons featured televoting - with viewers being invited to call the phone number during the show. Seasons 9-11 also featured telivoting and voting via social media. Season 16 featured voting integrated on the 10 App.
Seven Network format (seasons 12–15) In 2020, the Seven Network revived the series in a format inspired by the American and Canadian editions - with housemates deciding both nominations and evictions among themselves. The new format emphasised the competitive aspect of surviving the eviction process. As such, the housemates were allowed to strategise, politic and collude about the nominations and evictions. However, there were still be key differences compared to the American and Canadian formats, most prominently with the Australian public still deciding the eventual winner - rather than being decided by a "Jury" of evicted housemates (as is the case on the American and Canadian show).
Nominations: At the start of each round, the housemates compete in a "Nomination Challenge". The winner of the challenge is safe from eviction and get power over the nominations. Immediately after the challenge, Big Brother will call the winning housemate to the Diary Room to name their nominees and provide full reasons for their nominations. The number of nominees is determined by how far into the overall game housemates are, as the game starts with three nominees and reduces to two nominees towards the end of the game. Eviction: On eviction night, all housemates must vote to evict one of the nominees, with the exception of the nominating housemate (who will only cast a tie-breaker vote, if required), nor do the nominated housemates vote when there are only two nominees (on account of their votes cancelling the other's out). The eviction vote is by secret ballot, with housemates casting their votes orally in the Diary Room to Big Brother and must provide a reason for their vote. The nominee with the most votes is evicted from the house. Finale: At the end of the series when the grand final makes its way, the final three housemates that are left will face Australia's vote to determine the winner. This vote is conducted on a dedicated website, with voters voting for a winner. The finalist with the most votes is declared the winner of Big Brother.
Prize money The winner of Big Brother Australia receives a cash prize for being the last remaining housemate.
In seasons 1–3, 8–10 and 13–14, the prize was guaranteed A$250,000. Some seasons only mentioned the grand prize part-way through the series. Seasons 11 and 12 also intended to have a A$250,000 prize, but tasks and challenges during both seasons resulted in the prize decreasing. In season 11, the final prize was A$200,000 and in season 12 the prize was A$234,656. In season 4, the prize money was a guaranteed A$1,000,000. Seasons 5 and 6 continued to offer the A$1,000,000 but introduced a fine system. The winner of season 5 received $836,000, while the winner of season 6 received A$426,000. Season 7 was advertised as having no prize money. When the series began, it was revealed the grand prize would be based on the household's completion of weekly tasks. The grand-prize money was A$450,000. A variation of this twist was used on season 16, with the prize starting as A$100,000, and able to increase or decrease based on tasks and events in the house. The grand total was A$135,000. The shortened season 15 had a prize of A$100,000. In both celebrity spin-offs, Celebrity Big Brother Australia and Big Brother VIP Australia, the winner was awarded A$100,000 to the charity of their choice.