The Quietly Confident Quartet of Australia wins the men's 4 x 100 metre medley relay at the Moscow Olympics, the only time the United States has not won the swimming event at Olympic level.

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.