The 13th IAAF World Championships in Athletics (Korean: 2011년세계육상선수권대회) was an international athletics competition that was held in Daegu, South Korea. It started on 27 August 2011 and finished on 4 September 2011.

The United States topped the medal standings in the competition with 28 (12 gold, 9 silver, and 7 bronze). During the competition, 41 national records, 4 area records, 3 championship records, and 1 world record was set.

The championships were heavily affected by post-championship doping cases, particularly from the Russian team, who in subsequent years were stripped of eleven medals, seven of them gold.

On 4 April 2006, the IAAF (now World Athletics) announced that nine countries (United States, South Korea, Australia, Sweden, Spain, Russia, the United Arab Emirates, Croatia and Morocco) had submitted expressions of interest for hosting the 2011 World Championships.

When the seeking deadline passed on 1 December 2006, four candidate cities (Brisbane, Daegu, Moscow and Gothenburg) had confirmed their candidatures. Gothenburg backed out later that month, citing lack of financial support from the Swedish government.

Brisbane was announced as the Australian candidate with the Queensland Sport and Athletics Centre (formerly ANZ Stadium) as the proposed venue for a championships to be held in July or August. The stadium previously hosted the 1982 Commonwealth Games and 2001 Goodwill Games. Brisbane also had an unsuccessful bid for the 2009 World Championships in Athletics.

Daegu was the city chosen for the Korean bid, following on from an initial application to host the 2009 edition. Daegu had previously hosted the 2003 Summer Universiade and four matches of the 2002 FIFA World Cup. The World Championships in Athletics had never been staged in mainland Asia, although it has taken place twice in Japan.

The Russian bid had Moscow's Luzhniki Stadium as the proposed venue. The city hosted the 1980 Summer Olympics and the 2006 IAAF World Indoor Championships.