Monica Seles (Hungarian: Szeles Mónika, Serbo-Croatian:Monika Seleš, pronounced , born December 2, 1973) is a former World No. 1 professional tennis player and a member of the International Tennis Hall of Fame. She was born in Novi Sad, Yugoslavia (now Serbia) to Hungarian parents and became a naturalized United States citizen in 1994. According to published reports in Canadian and Hungarian news media (including two newspapers of record), she also received Hungarian citizenship in June 2007. She won nine Grand Slam singles titles, winning eight of them while a citizen of Yugoslavia and one while a citizen of the United States.

She became the youngest-ever champion at the 1990 French Open at the age of 16. She was the World No. 1 player in the women's game during 1991 and 1992, but in 1993 she was forced out of the sport for more than two years following an on-court attack in which a German spectator stabbed her in the back with a 10-inch-long knife. She enjoyed some success after returning to the tour in 1995, including a Grand Slam singles title at the 1996 Australian Open, but was unable to consistently reproduce her best form. Seles played her last professional match at the 2003 French Open, but her official retirement announcement was not issued until February 2008.

Seles began playing tennis at the age of six, coached by her father, Károly Szeles. In 1985 at the age of 11, she won the Orange Bowl tournament in Miami, Florida, and caught the attention of tennis coach Nick Bollettieri. In 1986, the Seles family moved from SFR Yugoslavia to the United States, and Seles enrolled at the Nick Bollettieri Tennis Academy, where she trained for two years.