Sung Si-Bak (Hangul: 성시백, Hanja: 成始柏, ; born February 18, 1987, in Seoul, South Korea) is a South Korean short track speed skater. At the 2007 Winter Universiade, he won all five short track speed skating events. Sung has won more than 20 World Cup races and earned two World Cup titles, in addition to skating on the winning World Championship 5000 m relay teams in 2007 and 2008. He qualified for the 2010 Winter Olympics in Vancouver, British Columbia, Canada. Sung was in medal contention leading into the final lap of the 1500 m event there, when a crash between him and a teammate led to his finishing in 5th place.