Andre Kirk Agassi ( AG-ə-see; born April 29, 1970) is an American former world No. 1 tennis player. He is an eight-time major champion and an Olympic gold medalist, as well as a runner-up in seven other majors. Agassi is widely considered one of the greatest tennis players of all time.

Agassi is the second of five men to achieve the career Grand Slam in the Open Era and the fifth of eight overall to make the achievement. He is also the first of two men to achieve the career Golden Slam (career Grand Slam and Olympic gold medal), as well as the only man to win a career Super Slam (career Grand Slam, plus the Olympic gold medal and the year-end championships).

Agassi was the first man to win all four singles majors on three different surfaces (hard, clay and grass), and remains the most recent American man to win the French Open (in 1999) and the Australian Open (in 2003). He also won 17 Masters 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. 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.