Julia Elizabeth Smit (born December 14, 1987) is an American competition swimmer, two-time Olympic medalist, and former world record-holder in two events.

She has won a total of nine medals in major international competition, six golds, two silvers, and one bronze spanning the Olympics and Pan American Games.

Smit received an athletic scholarship to attend Stanford University, where she was a five-time national champion for the Stanford Cardinal swimming and diving team, having won the 400-yard individual medley three times (2008, 2009, 2010) and the 200-yard individual medley twice (2009, 2010).

[2] Smit received the 2009–10 Honda Sports Award for Swimming and Diving, recognizing her as the outstanding college female swimmer of the year.

At the 2009 Duel in the Pool, Smit reclaimed the world record in the short course 400 m individual medley with a time of 4:21.04.