Lilly King (born February 10, 1997) is an American swimmer. At the 2016 Summer Olympics she won the gold medal in the 100 meter breaststroke competition and also won a gold medal in the women's 4 × 100 m medley relay, in which she swam the breaststroke leg. She is the current world record holder in 100-metre and 50-metre breaststroke (long course).
King was born and raised in Evansville, Indiana, the daughter of Mark and Ginny King. Mark ran track and cross-country at Indiana State University and Ginny swam for Eastern Kentucky University and Illinois State University. King's younger brother Alex is a walk-on swimmer at the University of Michigan. King attended FJ Reitz High School, where the school's swim team shared Lloyd Pool with five other teams. The lanes at Lloyd Pool were often crowded with swimmers below King's ability, so in order to help compensate, King added several morning practices a week with the local masters team and joined a competitive swim team called the Newburgh Sea Creatures.