The 2012 World Junior Championships in Athletics was an international athletics competition for athletes qualifying as juniors which was held at the Estadi Olímpic Lluís Companys in Barcelona, Catalonia, Spain, on 10–15 July 2012. A total of 44 athletics events were contested at the championships, 22 by male and 22 by female athletes.

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.