The IRB Junior World Championship was the international rugby competition for the Under-20 players in the IRB nations. It is run by the IRB, the International Rugby Board, which is the organisation that governs and controls the game of rugby throughout the world.
The JWC was first held in 2008. The competition replaced the previous age grade competitions that existed at that time. These were the Under-19 and Under-21 World Championships.
The first championship in 2008 was held in Wales and had 16 teams competing in it. The number of teams playing in the competition was reduced to 12 teams in 2010.
There was also another competition started at the same time as the Junior World Championship. This was the Junior World Rugby Trophy, which is a 2nd tier competition for under-20 teams, with 8 teams taking part. There is promotion and relegation between the two competitions, with the winner of the JWRT playing in the JWC the following year and the last placed team in the JWC playing in the JWRT in the following year.
In 2015 the name was changed to the World Rugby Under 20 Championship, in line with the name change of the IRB to World Rugby. The Junior World Rugby Trophy was also renamed the World Rugby Under 20 Trophy and still acts as the feeder for the Championship competition.