Justine Henin (born 1 June 1982 (:Category:1982 births)), formerly known as Justine Henin-Hardenne (2002-2007), is a professional Belgian tennis player (List of female tennis players), currently ranked the World No. 23. Henin has won 42 WTA (Womens Tennis Association) singles titles and seven Grand Slam (Grand Slam (tennis)) singles titles, including four French Open (French Open (tennis)) titles, one Australian Open title, and two US Open (U.S. Open (tennis)) titles. She has also won the year-ending Sony Ericsson Championships twice and the singles gold medal at the 2004 Summer Olympics (Tennis at the 2004 Summer Olympics).

Tennis experts cite her mental toughness, the completeness and variety of her game, her footspeed and footwork, and her one-handed backhand (which John McEnroe has described as the best single-handed backhand in the womens or mens game) as the principal reasons for her success.

Many critics and all-time-great players consider Henin to be the single best tennis player of her generation. Upon Henins first retirement from the WTA in the early part of the 2008 season, Billie Jean King said that "pound for pound, Henin is the best tennis player of her generation." as well as that "Justine is the best womens athlete Ive ever seen." Andre Agassi said of Henin, "Justine Henin is one of the most talented women ever to have played the game of tennis." 18 time Grand Slam winner Martina Navratilova said that "She is head and shoulders above everyone else?" John McEnroe concurred, saying that Henin is "The player I most like to watch. She has the best backhand in the game?male or female." Henin made a return to the WTA in early 2010, losing the final of the Australian Open in only her 2nd tournament back.

Henin sits at 2nd place on the WTA tour of active players with most titles won (42), 2nd only to Venus Williams 43, although she has played for about 4 years less than Venus (became pro 2 years after Venus and her 2 year retirement). She is also only one of 3 active WTA players to have reached the finals of all four grand slams, the other two being Venus Williams and Serena Williams. In addition, for active WTA players, along with Serena Williams and Maria Sharapova, Henin has won at least 3 out of the 4 Grand Slams. Henin is also the only currently active WTA player who has won a Grand Slam tournament at least three times in a row (Roland Garros 05 to 07).