The 11th FINA World Swimming Championships (25m) were held in Istanbul, Turkey on 12–16 December 2012. This swimming-only championships took place in the Sinan Erdem Dome; all events were swum in a 25-meter (short-course) pool.

The United States topped the medal standings with a total of 27 medals and had the most gold medals with 11. A total of 18 championship records were set and 2 world records (both set by American Ryan Lochte) broken. Lochte and Hungarian Katinka Hosszú were named the best male and female swimmers of the competition. Lochte finished the meet with 8 total medals (breaking his previous record of 7 set in 2010) and Hosszú had 5 total medals.

FINA announced on 12 April 2008 that Istanbul had defeated the only other bidder Vienna, Austria after a meeting of the FINA Bureau in Manchester, UK.

The events took place at the Sinan Erdem Dome, which has a seating capacity of 22,500.

The swimming competition featured races in a short-course (25 m) pool in 40 events (20 for males, 20 for females; 17 individual events and 3 relays for each gender). Prelim events were held in the morning session and semi-finals/final in the evening session.

In June 2013, Danish swimmer Mads Glæsner was stripped by FINA of a gold and bronze medal from the 400- and 1500-meter freestyle after testing positive for levomethamphetamine.

In January 2014 the Court of Arbitration for Sport partially overturned FINA's ruling and returned the gold medal in 1500 m freestyle.

161 nations entered the competition. Ecuador, currently suspended by FINA due to government interference, participated under the FINA flag. Venezuela later withdrew.