Alexis Noel Thompson (born February 10, 1995) is an American professional golfer who plays on the LPGA Tour. She has won a total of 15 professional titles during her career, including 11 victories on the LPGA Tour. Her one major title came at the 2014 Kraft Nabisco Championship. She has represented the United States at seven Solheim Cups, winning in 2015, 2017 and 2024.

In 2007, aged 12, Thompson became the then youngest ever golfer to qualify for the U.S. Women's Open. In 2010, she was part of the United States team that won the Curtis Cup, and she turned professional afterwards aged 15. In September 2011, Thompson set a record as the then youngest-ever winner of an LPGA tournament, aged 16 years, seven months, and eight days, when she won the Navistar LPGA Classic. Three months later, she became the second-youngest winner of a Ladies European Tour event, after capturing the Dubai Ladies Masters, and in 2013 she became the youngest player to compete for the United States in a Solheim Cup. She won her first and only major championship at the 2014 Kraft Nabisco Championship at the age of 19, making her the second youngest LPGA golfer to have won a major at the time.

Thompson's pursuit of a second major victory has resulted in several near-misses. She finished second at the 2015 Evian Championship, and she lost in a playoff at the 2017 ANA Inspiration after being penalized a total of four penalty strokes during the tournament for replacing her ball incorrectly and subsequently signing an incorrect scorecard. She has also recorded further runner-up finishes at the 2019 U.S. Women's Open and the 2022 Women's PGA Championship, and let slip a five-stroke lead during the final round of the 2021 U.S. Women's Open where she ended up in third place.

Thompson grew up in a home that was situated immediately adjacent to Eagle Trace Golf Club in Coral Springs, Florida. She is the youngest of three siblings: her two brothers Nicholas and Curtis also became professional golfers. She began playing golf at age 5, and started playing competitively two years later. Thompson was home-schooled, getting up early in the morning to carry out her studies before playing golf in both the mornings and afternoons. She graduated in July 2012.

In 2003, Thompson was the U.S. Kids under-8 World Champion and she won the under-9 title the following year. In 2007, aged 12, she became the then youngest ever player to qualify for the U.S. Women's Open. At the tournament, she shot 76-82 and failed to make the cut. Her record was later surpassed by Lucy Li in 2014 who was 11. During 2007, Thompson won the Aldila Junior Classic to become the second-youngest winner in American Junior Golf Association (AJGA) history, and she also won the Westfield Junior PGA Championship to become the youngest winner in Junior PGA Championship history.

In 2008, Thompson won the U.S. Girls' Junior at Hartford Golf Club, overcoming Karen Chung five and four to seal the title and become the second youngest ever winner of the trophy. That year, she again qualified for the U.S. Women's Open, where she failed to make the cut. She also competed in the Junior Ryder Cup in Bowling Green, Kentucky, in which the United States triumphed 22‍–‍2 over Europe.

Thompson qualified for the U.S. Women's Open for the third straight year in 2009, and she made the cut for the first time, finishing tied for 34th. She then clinched victory in a playoff at the Verizon Junior Heritage. Thompson was selected to play at the 2009 Junior Solheim Cup, and she helped the United States record a 15.5-8.5 victory over Europe at Aurora Country Club, in Aurora, Illinois.

Thompson played as an amateur in the Women's Australian Open, where she finished T16th, and she made the cut at the 2010 Kraft Nabisco Championship, finishing T24th. She represented the winning United States team in the 2010 Curtis Cup competition and she went undefeated, winning four matches and tying in a fifth. The United States defeated Great Britain and Ireland 12.5-7.5.