האח הגדול אוסטרליה הוא הגרסה האוסטרלית לתוכנית הריאליטי הבינלאומית האח הגדול.

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.