Coordinates: 27°51′31.96″S 153°18′53.27″E  /  -27.8588778 , 153.3147972

Big Brother Australia 2007 was the seventh season of the Australian reality television series Big Brother Australia . Episodes were broadcast on Network Ten in Australia, and the first episode aired on April 22, 2007. Auditions were held throughout November and December 2006, taking place in Brisbane, Sydney, Melbourne, Adelaide, Perth, Hobart and Darwin.

Despite a drop in ratings compared to previous series, and a number of controversies, the then Big Brother executive producer Kris Noble considers the year's series a success. It was also announced by Gretel Killeen, the host of the series, at the end of this year's finale that Big Brother will return for an eighth series in 2008. In the finale broadcast July 30, 2007, Aleisha Cowcher was announced winner of Big Brother Australia 2007 by the closest winning margin ever in Australian voting history, 51% - 49% an actual split of just 65 votes which was announced on the news the following day. This series was the last to be hosted by Gretel Killeen.