The Australian national under-21 rugby union team formerly represented Australia on a national level in age graded rugby union. The team competed at the Under 21 Rugby World Championship, and featured in three championship finals, though they never won the event, losing to South Africa in 2002, New Zealand in 2003 and South Africa again in 2005. Australia finished in fourth place at the final under-21 world championship, held in France in 2006.
In 2008, the International Rugby Board scrapped its under-21 and under-19 world championships in favour of a single under-20 competition, the IRB Junior World Championship. Australia accordingly replaced its under-21 and under-19 sides with a new under-20 side.
| Year | Champions | Score | Runners-up | Venue |
|---|---|---|---|---|
| 2002 | South Africa  |
24-21 |  Australia |
Johannesburg, South Africa |
| 2003 | New Zealand  |
21-10 | Australia |
Oxford, England |
| 2005 | South Africa |
20-15 | Australia |
Mendoza, Argentina |
