Kathryn Elise Hoff (born June 3, 1989) is an American former competition swimmer, Olympic medalist, and former world record-holder. Though Hoff was known for her success in the 200- and 400-meter individual medley, she was a very capable swimmer in many events, ranging from the four 200-meter events to the 800-meter freestyle. She represented the United States at the 2004 Summer Olympics and 2008 Summer Olympics, in which she captured a silver and two bronze medals.
Hoff qualified for the 2004 Summer Olympics at the age of 15; she failed to medal in both of the events in which she competed.
At the 2005 World Aquatics Championships, Hoff set a championships record for her time of 2:10.41 in the women's 200 m individual medley. Hoff received two more gold medals at the competition, one in the 400-meter medley and the other for the 4×200-meter freestyle, with teammates Natalie Coughlin, Whitney Myers, and Kaitlin Sandeno.