Kim Antonie Lode Clijsters is a Belgian former professional tennis player. Clijsters reached the world No. 1 ranking in both singles and doubles, having held both rankings simultaneously in 2003. She won six major titles, four in singles and two in doubles.

Kim Clijsters was born on 8 June 1983 in Bilzen, a small town in northeastern Belgium. She grew up with her younger sister Elke in the nearby town of Bree in the Flemish province of Limburg. Kim is the daughter of Lei Clijsters and Els Vandecaetsbeek, both of whom were accomplished athletes. Her mother Els was a Belgian national artistic gymnastics champion. Her father Lei was a professional football defender who played for a variety of clubs in the top-flight Belgian First Division, including KV Mechelen with whom he won the UEFA Cup Winners' Cup in 1988. He was also a member of the Belgium national football team, tallying 40 caps and competing in two World Cups. Clijsters credits her parents for giving her a footballer's legs and a gymnast's flexibility. She also attributes her success to the freedom they gave her when she was a young player, saying, "Without the support I've had from my family, I wouldn't be where I am. They've let me make my own decisions."