Kim Si-woo born 28 June 1995), also known as Si Woo Kim, is a South Korean professional golfer who plays on the PGA Tour. He won the 2017 Players Championship to become the youngest ever winner of the event at age 21.
Kim played on the Web.com Tour in 2014, making 15 of 19 cuts including a third-place finish at the Cleveland Open. In 2015, he won his first Web.com Tour event, the Stonebrae Classic, in July. He was the second-youngest winner in Web.com Tour history, after Jason Day. He finished 2015 in tenth place in the Web.com Tour money list, to earn a place on the PGA Tour for 2016.
His first win on the PGA Tour came at the 2016 Wyndham Championship. At 21, he was the season's youngest winner.