Andre Kirk Agassi (born April 29, 1970) is an American retired professional tennis player and former world No. 1 whose career spanned from the late 1980s to the early 2000s.

In singles, Agassi is an eight-time Grand Slam champion and a 1996 Olympic gold medalist, as well as being a runner-up in seven other Grand Slam tournaments. During the Open Era, Agassi was the first male player to win four Australian Open titles, a record that was later surpassed by Novak Djokovic when he won his fifth title in 2015, and then by Roger Federer in 2017. Agassi is one of five male singles players to achieve the Career Grand Slam in the Open Era and one of eight in history, the first of two to achieve the Career Golden Slam (Career Grand Slam and Olympic Gold Medal, the other being Rafael Nadal), and the only man to win the Career Golden Slam and the ATP Tour World Championships: a distinction dubbed as a "Career Super Slam" by Sports Illustrated.

Agassi was the first male player to win all four Grand Slam tournaments on three different surfaces (hard, clay and grass), and the last American male to win both the French Open (in 1999) and the Australian Open (in 2003). He also won 17 ATP Masters Series titles and was part of the winning Davis Cup teams in 1990, 1992 and 1995. Agassi reached the world No. 1 ranking for the first time in 1995 but was troubled by personal issues during the mid-to-late 1990s and sank to No. 141 in 1997, prompting many to believe that his career was over. Agassi returned to No. 1 in 1999 and enjoyed the most successful run of his career over the next four years. During his 20-plus year tour career, Agassi was known by the nickname "The Punisher".

After suffering from sciatica caused by two bulging discs in his back, a spondylolisthesis (vertebral displacement) and a bone spur that interfered with the nerve, Agassi retired from professional tennis on September 3, 2006, after losing in the third round of the US Open to Benjamin Becker. He is the founder of the Andre Agassi Charitable Foundation, which has raised over $60 million for at-risk children in Southern Nevada. In 2001, the Foundation opened the Andre Agassi College Preparatory Academy in Las Vegas, a K-12 public charter school for at-risk children. He has been married to fellow tennis player Steffi Graf since 2001.

ndre Agassi was born in Las Vegas, Nevada to Emmanuel "Mike" Agassi, a former Olympic boxer from Iran and Elizabeth "Betty" Agassi (née Dudley). His father is of Armenian and Assyrian heritage. One of his ancestors changed his surname from Armenian Aghassian to less noticeable Agassi as "a skin-saving measure during a time when Turks frequently used Armenians for target practice".Andre Agassi's mother, Betty, is a breast cancer survivor. He has three older siblings – Rita (last wife to Pancho Gonzales), Philip and Tami. Andre was given the middle name Kirk after Kirk Kerkorian, an Armenian American billionaire. Agassi, a waiter at Tropicana Las Vegas, met Kerkorian in 1963.

Agassi at the age of 12 (with his good friend and doubles partner Roddy Parks) won the 1982 National Indoor Boys 14s Doubles Championship in Chicago. Agassi describes more of his memorable experiences and juvenile pranks with Roddy in his book Open.

At the age of 13, Agassi was sent to Nick Bollettieri's Tennis Academy in Florida. He was meant to stay for only three months, because that was all his father could afford. After thirty minutes of watching Agassi play, Bollettieri, deeply impressed by his talent, called Mike and said: "Take your check back. He's here for free."Agassi then dropped out of school in the ninth grade to pursue a full-time tennis career.