Kim Antonie Lode Clijsters is a Belgian former professional tennis player. She was ranked as the world No. 1 in women's singles by the Women's Tennis Association (WTA) for 20 weeks, and as the world No. 1 in women's doubles for 4 weeks, having held both rankings simultaneously in 2003. She won 41 singles titles and 11 doubles titles on the WTA Tour, including four singles majors and two doubles majors (both partnering Ai Sugiyama), as well as three singles titles at the Tour Finals.
Clijsters competed professionally from 1997 in an era in which her primary rivals were compatriot Justine Henin and Serena Williams. Coming from a country with little historical success in tennis, she established Belgium as a leading force in women's tennis alongside Henin, as the two of them led their country to their first Fed Cup crown in 2001 and were the top two players in the world in late 2003. Following defeats in all of her first four major singles finals, Clijsters finally won her first singles major at the 2005 US Open.
Plagued by injuries and having lost desire to compete, Clijsters retired from tennis in 2007 at the age of 23 to get married and have a daughter.