The 2008 World Junior Championships in Athletics is the 2008 version of the World Junior Championships in Athletics. It was held in Bydgoszcz in Poland at the Zdzisław Krzyszkowiak Stadium between 8 and 13 July 2008. Previously Bydgoszcz hosted the 1999 World Youth Championships.

The World Athletics U20 Championships is a biennial world championships for the sport of athletics organised by the World Athletics, contested by athletes in the under-20 athletics age category (19 years old or younger on 31 December in the year of the competition.