Regan Smith (/ˈreɪɡən/; born February 9, 2002) is an American competitive swimmer who specializes in backstroke and butterfly events.

When Smith was 12, she achieved multiple new age-group records and won medals at high school state meets.

[11] In August 2018, Smith won her first senior international medal by taking bronze in the 200 m backstroke at the 2018 Pan Pacific Championships in Tokyo.

[12] At the 2019 World Championships in Gwangju, South Korea, Smith competed in one individual event, the 200 m backstroke.

[14] The next day in the final, Smith won her first World Championship title, claiming gold by a margin of more than two and a half seconds.

She was well under her world record pace with a 100-meter split of 59.45 (a time that would have placed sixth in the 100 m backstroke final held earlier).

She won gold along with Lilly King, Kelsi Dahlia, and Simone Manuel, with a world-record time of 3:50.40 to break the previous mark of 3:51.55 set in 2017.

She was also named 2019 National Age Group Swimmer of the Year (17–18 year-olds) by SwimSwam, her fourth such award of her career.

[27][28] On day four of the Olympic Trials, Smith advanced to the final of the 200 m butterfly with a time of 2:07.89 and ranking second overall in the semifinals.

[40] In the prelims of the 100 m backstroke on day two of competition, she advanced to the semifinals and set a new Olympic record in the event with a time of 57.96, which was broken in the last preliminary heat by Kaylee McKeown, who swam a 57.88.

[47] In the evening of the fourth day of competition, Smith swam the fourth-fastest time out of all swimmers in the 200 m butterfly prelims and qualified for the semifinals.

[53][54][55] On day nine of competition, Smith competed in the 4×100 m medley relay final as the backstroke leg for the U.S. alongside Lydia Jacoby, Torri Huske, and Abbey Weitzeil.

[64][66] On the fourth and final day of competition, she won the 200 y butterfly with a 1:50.99 and helped to win the 4×100 y freestyle relay in 3:09.06, splitting a 47.41 for the third leg.

[68] For her second event of the first day, she helped win the 4×200 y freestyle relay in a pool record time of 6:48.30, swimming a 1:43.35 for the third leg.

[70] She achieved another third-place finish in her second event of the evening, the 4×100 y medley relay, where she split a 49.81 for the backstroke leg to contribute to a final time of 3:25.63.

She started training with coach Bob Bowman and the Sun Devils, based at Arizona State University.

[79] On day three of the World Championships, held in June in Budapest, Hungary, Smith won the gold medal in the 100 m backstroke with a time of 58.22, finishing less than two-tenths of a second ahead of silver medalist Kylie Masse.

[80][81][82] Two days later, Smith started off the evening finals session with a fourth-place finish in the 200 m butterfly in a time of 2:06.79.

[83] Approximately 30 minutes later, she concluded the day with a tie for fifth-place in the 50 m backstroke, finishing 0.07 seconds behind bronze medalist Analia Pigrée with a time of 27.47.

[84] For her final event of the championships, the 4×100 m medley relay on day eight, she led-off with a 58.40 to contribute to the gold medal-winning time of 3:53.78.

[89][90] For her third gold medal, she won the 100 m backstroke with a championship record of 57.95, which was 0.68 seconds faster than the former mark set in 2019 by Phoebe Bacon.

[91][90][92] On day four of four, Smith won the gold medal in the 200 m backstroke with a championship record time of 2:05.28, finishing over a second ahead of silver medalist Summer McIntosh.

[104] For her final race of the competition, Smith swam the backstroke leg of the 4×100 medley relay with a split of 57.68.

With a time of 3:52.08, the team consisting of Smith, Lilly King, Gretchen Walsh, and Kate Douglass, won the gold medal.

[103][105] At the 2023 U.S. Open Championships in Greensboro, North Carolina, Smith's performance was highlighted by her results on the final night.

She swam in the heats of the 4×100 mixed medley relay, and the U.S. won in the final, earning Smith her first Olympic gold medal.

Later that night, she swam the butterfly leg in the 4 × 50 m mixed medley final, helping the U.S. team win bronze.