Justine Henin (French pronunciation: ; born 1 June 1982), between 2002 and 2007 Justine Hénin-Hardenne, is a Belgian former professional tennis player known for her all-court style of play and notably being one of the few female players to use a single-handed backhand. She spent a total of 117 weeks as the world No. 1 and was the year-end No. 1 in 2003, 2006 and 2007.
Henin won seven Grand Slam singles titles; winning the French Open in 2003, 2005, 2006 and 2007, the US Open in 2003 and 2007 and the Australian Open in 2004. At Wimbledon, she was the runner-up in 2001 and 2006. She also won a gold medal in the women's singles at the 2004 Olympic Games and won the year-ending WTA Tour Championships in 2006 and 2007. In total, she won 43 WTA singles titles.
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 described as "the best single-handed backhand in both the women's or men's game") as the principal reasons for her success. She retired from professional tennis on 26 January 2011, due to a chronic elbow injury. In June 2011, she was named one of the "30 Legends of Women's Tennis: Past, Present and Future" by Time. She is widely considered one of the greatest female tennis players of all time. In 2016, she became the first Belgian tennis player inducted into the International Tennis Hall of Fame.