Tonny de Jong (born 17 July 1974) is a former Dutch speed skater, who was raised in Heerenveen and now lives in Calgary with Canadian speed skater Mark Knoll, whom she married in 2003. She won three Dutch Allround Championships and numerous gold medals on the 3000 m and the 5000 m at the Dutch Single Distance Championships. In 1997 and 1999 she became European Allround Champion. De Jong was the first skater who mastered the clap skate.