Big Brother Australia (also known simply as Big Brother) is an Australian reality show based on the international Big Brother format created by John de Mol.

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.

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. In 2019 the Seven Network picked up the series, which is produced by Endemol Shine Australia. All eleven previous seasons were produced by Endemol Australia and Endemol Southern Star. The twelfth season aired in 2020. The series was renewed for a 13th season in June 2020. Seven has also commissioned a new celebrity edition titled Big Brother VIP to air on 1 November 2021.The Ten and Nine iterations of the series used a compound located at the Dreamworld theme park, on the Gold Coast, Queensland, as the Big Brother House. It has since been abandoned and vandalised. In June 2019, the house was set ablaze and burnt down entirely. The entire compound was demolished by Dreamworld in August 2019. A new Big Brother House located on Sydney Harbour's North Head is used for Seven's iteration of the series in season 12, although this house has since been pulled down following season 13. The following VIP season was filmed at a newly built compound in Sydney Olympic Park, which has been the filming location for the main series since season 14. The fifteenth season aired between 6 November 2023 and 6 December 2023 and was won by Tay & Ari Wilcoxson.

On 18 October 2023, the series was renewed for its sixteenth season at Seven's 2024 upfronts event. It will air sometime in 2024, the Uncut spin-off will also be returning for the second season in a row.