Australia (KA–5) is an Australian 12-metre-class America's Cup racing yacht that twice challenged unsuccessfully for the America's Cup in 1977 and 1980. Designed by Ben Lexcen in association with the Dutch designer Johan Valentijn for Alan Bond, Australia failed to win a single race against the 1977 defender, Courageous (US-26), but won one race against the 1980 defender, Freedom (US-30). Australia resides in Sydney, Australia.

The America's Cup is a sailing competition and the oldest international competition still operating in any sport. America's Cup match races are held between two sailing yachts: one from the yacht club that currently holds the trophy and the other from the yacht club that is challenging for the cup. The winner is awarded the America's Cup trophy, informally known as the Auld Mug. Matches are held several years apart on dates agreed between the defender and the challenger. There is no fixed schedule, but the races have generally been held every three to four years. The most recent America's Cup match took place in March 2021.