Australia competed at the 1980 Summer Olympics in Moscow, USSR. In partial support of the American-led boycott of the 1980 Summer Olympics Australia competed under the Olympic Flag. 120 competitors, 92 men and 28 women, took part in 92 events in 17 sports.Flag bearers Denise Boyd (athletics) and Max Metzker (swimming), Australias first joint-flag carriers, carried the Olympic flag in the opening ceremony instead of the national flag. Countries marched in order of the Russian alphabet, and Australia was therefore second in the parade of nations, following Greece, which has traditionally led the march since 1928.

The Quietly Confident Quartet was the self-given name of the Australian men's 4 × 100 metres medley relay swimming team that won the gold medal at the 1980 Summer Olympics in Moscow. The United States boycotted the Moscow Olympics in protest against the Soviet invasion of Afghanistan and, through the 2016 Olympics, the Australian victory remains the only occasion the United States has not won the event at Olympic level since its inception in 1960. The quartet consisted of backstroker Mark Kerry, breaststroker Peter Evans, butterflyer Mark Tonelli and freestyler Neil Brooks. The team was nominally led by its oldest member Tonelli, who was 23 and was also a spokesperson for the Australian athletes' campaign for their right to compete at the Olympics against the wishes of the Fraser Government. The team was seen as an unlikely prospect to win; all four of the swimmers had clashed with swimming authorities over disciplinary issues and three experienced suspension or expulsion from the Australian team during their careers.

Australia had previously won medals in the event, but was not regarded as one of the favourites for the gold, as the Soviet Union, Great Britain, and Sweden all fielded more decorated swimmers over the component legs of the relay. After the backstroke leg, Australia was in fourth place and more than a second in arrears of the Soviet leaders. However, Evans was the fastest among the breaststrokers and moved the team into second position at the halfway point in the race; and Tonelli, a makeshift butterflyer, completed his leg in a time much faster than his previous best, allowing Australia to keep the Soviet lead reasonable. Australia's anchor swimmer Brooks overtook his more credentialled Soviet counterpart Sergey Koplyakov in the latter half of the final leg to secure a narrow victory. The quartet disbanded after the Olympics due to Tonelli's retirement, although some of the members continued to be present in the relay team at various times alongside new swimmers. By 1986, all four members of the 1980 team had retired from international competition.