The 15th FINA World Championships (Catalan: Campionat Mundial de Natació de 2013, Spanish: Campeonato Mundial de Natación de 2013) were held from 20 July to 4 August in Barcelona, Catalonia, Spain. The 2013 World Championships featured 6 aquatics disciplines: swimming, water polo, diving, high diving, open water, and synchronised swimming.

The Championships were originally awarded to Dubai, United Arab Emirates, in July 2009; however, Dubai withdrew as host in May 2010. FINA then re-bid the meet, and Barcelona was selected on September 26, 2010.

The venues that hosted the events were previously used for the 2003 World Aquatics Championships:

This was the first time the World Aquatic Championships included high diving.

The opening ceremonies took place on July 19, 2013.

  *   Host nation (Spain)

On the first day of competition on July 20, American Haley Anderson won the first gold of the competition in the women's 5 km, just beating Brazilian Poliana Okimoto 56:34.2 to 56:34.4. In the second event on day one, Tunisian Oussama Mellouli won the men's 5 km race with a time of 53:30.4.

The following world records were established during the competition: