Ryan Steven Lochte (/ˈlɒkti/ LOK-tee; born August 3, 1984) is an American former competitive swimmer and 12-time Olympic medalist. He is the third-most decorated swimmer in Olympic history measured by total number of medals, behind only Michael Phelps and Katie Ledecky. Lochte's seven individual Olympic medals rank second in history in men's swimming (again to Michael Phelps), tied for second among all Olympic swimmers. He currently holds the world records in the 4×200-meter freestyle (long course).

Lochte's success has earned him SwimSwam's Swammy Award for U.S. Male Swimmer of the Year in 2013, the World Swimmer of the Year Award, and the American Swimmer of the Year Award twice. He has also been named the FINA Swimmer of the Year three times. He has won a total of 90 medals in major international competition (54 gold, 22 silver and 14 bronze) spanning the Olympics, the World Championships Pan American Games and Pan Pacific Championships, including six Olympic gold medals and 39 world championship titles.

Lochte specialized in the backstroke and individual medley but was also a freestyle and butterfly swimmer. He is noted for the speed and distance he attained while kicking underwater. Lochte is also known for the dominance he held in the short course format (25-yard and 25-meter-long pools). Lochte swam the 100-meter individual medley in a then-world record 50.71 seconds on December 15, 2012 at the FINA World Championships in Istanbul, Turkey. At this same event, he was also credited with swimming the then-fastest 200-meter individual medley, finishing in 1 minute 49.63 seconds.

In 2016, Lochte generated international controversy when he claimed that he and three other American swimmers had been pulled over and robbed by armed men with police badges while in Rio de Janeiro, Brazil, at the 2016 Summer Olympics. While initial news stories reported that Lochte and three other US swimmers had been robbed at gunpoint after a night out in Rio, later details emerged that the "armed robbers posing as police" were actually security guards at a gas station where the swimmers had urinated outside the bathroom and Lochte allegedly vandalized a framed poster, and ended with the swimmers providing money to the guards. Lochte apologized for not being more candid about the gas station dispute, and subsequently lost four major sponsorships. On September 8, both the U.S. Olympic Committee and USA Swimming suspended Lochte for 10 months and Bentz, Conger, and Feigen for four months. Additionally, Lochte was required to complete 20 hours of community service, and Bentz was required to complete 10 hours. All were made ineligible for financial support during their suspensions, removed from the U.S. Olympic delegation to the White House, barred from U.S. Olympic training centers, and blocked from attending USA Swimming's year-end Golden Goggles celebration. Lochte was charged in Brazil with falsely reporting a crime. The scandal gained significant media attention both during the games and after their conclusion. In July 2017, the court in Brazil dismissed the charges against Lochte, saying his actions "did not rise to the level of filing a false crime report."

On July 23, 2018, the U.S. Anti-Doping Agency imposed a 14-month suspension from competition on Lochte because he had received a "prohibited intravenous infusion." Lochte immediately accepted the sanction. On May 24, 2018, the same day he had received the infusion, Lochte had posted a picture – since deleted – on Instagram "showing him receiving an intravenous injection of what he says were 'vitamins'," even though the USADA bans "intravenous infusions of permitted substances at volumes greater than 100 millilitres [3.5 imp fl oz; 3.4 US fl oz] in a 12-hour period without a special 'Therapeutic Use Exemption'," Vox reported.

Lochte was born in Rochester, New York, the son of Ileana "Ike" Aramburu-Lochte and Steven R. Lochte. His mother is a Cuban of Basque descent and was born and raised in Havana, while his father is of Dutch, English, and German descent. He has two older sisters, Kristin and Megan, and two younger brothers, Devon and Brandon. During his early childhood, his family lived in Bristol, New York where he attended Bloomfield Central Schools. The family moved to Florida when Ryan was 12 so his father could coach swimming.

Lochte only began taking swimming seriously when he was in junior high school. His father said, "I would send him to go shower when he was messing around. He spent more time in the showers than he did in the pool." At 14 years old, his loss at the Junior Olympics changed his attitude. He later commented: "I suddenly said, 'I'm sick of losing'. After that I trained hard and I never lost there again."

Lochte attended the University of Florida and graduated in 2007, majoring in sport management. As a member of the Florida Gators swimming and diving team, he swam for coach Gregg Troy in National Collegiate Athletic Association (NCAA) and Southeastern Conference (SEC) competition from 2004 to 2007. At Florida, Lochte was the NCAA Swimmer of the Year twice, a seven-time NCAA champion, a seven-time SEC champion, and a 24-time All-American. At the 2006 NCAA Men's Swimming and Diving Championships, during his senior year, Lochte won national titles in all three of his individual events, setting U.S. Open and American records in the 200-yard individual medley and 200-yard backstroke. He also broke Tom Dolan's nearly decade-old NCAA record in the 400-yard individual medley.