Sloane Stephens (born March 20, 1993) is an American professional tennis player. She has been ranked as high as world No. 3 in singles by the Women's Tennis Association. Stephens has won eight WTA Tour-level singles titles, including the 2017 US Open. She was also the runner-up at the 2018 French Open. She has a career-high doubles ranking of world No. 63, and has won one WTA Tour doubles title.

Born to athletic parents, Stephens was introduced to tennis in Fresno, California. She became a promising junior player, reaching a junior ranking of world No. 5 and winning three out of four major girls' doubles titles in 2010 partnering Tímea Babos.

At 19 years old, Stephens rose to prominence by reaching the semifinals at the 2013 Australian Open, defeating world No. 3 Serena Williams en route. Although she reached No. 11 towards the end of 2013, she regressed and fell outside the top 25 at the end of 2015. Stephens switched to a new coach, Kamau Murray, under whom she returned to an elite level and won three WTA titles in the first half of 2016. Her successful year was cut short by a foot injury that kept her out for months.

Stephens returned from injury in the middle of 2017 and won the US Open in just her fifth tournament back, being awarded WTA Comeback Player of the Year for her successful season. In 2018, she continued her success by winning her first Premier Mandatory title at the Miami Open, reaching a second major final at the French Open, entering the top 10 for the first time, and finishing runner-up at the WTA Finals.

Stephens was born on March 20, 1993, in Plantation, Florida, to Sybil Smith and John Stephens, both of whom were accomplished athletes. Her mother was the first African-American woman to be named a first-team All-American swimmer in Division I history. She is enshrined in the Boston University Athletic Hall of Fame and recognized as the greatest swimmer in the history of the university. Stephens's father was a Pro Bowl running back for the New England Patriots in the National Football League. Pro Football Hall of Famer Raymond Berry regarded him as the best athlete he had ever seen.

Smith left Stephens's father after his multiple arrests in 1994. Stephens was raised by her mother and her stepfather, Sheldon Farrell, who married Smith in 1997 and worked as a business consultant. Her younger half-brother John Stephens Jr. plays tight end in the NFL. She also has another younger half-brother, Shawn Farrell, who played baseball and football at Notre Dame High School outside of Los Angeles. Stephens did not talk with her biological father until she was 13 years old, when he expressed interest in getting to know her after being diagnosed with degenerative bone disease. Even though they only met a few times in person, the two of them developed a close relationship remotely. Stephens's stepfather died from cancer in 2007, while her biological father died in a car crash in 2009.

Stephens moved to her mother's hometown of Fresno in California at the age of two. She started playing tennis at the age of nine at the Sierra Sport and Racquet Club, a tennis facility located across the street from her house where her stepfather regularly played and her mother was taking lessons. Former top 100 player Francisco González, the head of tennis at the club, recognized Stephens had impressive ability given her limited experience and recommended her to pursue more rigorous training opportunities. Two years after she started playing tennis, Stephens relocated to Boca Raton in Florida. She began training at the Evert Tennis Academy founded by John Evert and also run by his sister, International Tennis Hall of Famer Chris Evert. The following year at age 12, Stephens switched to the Nick Saviano High Performance Tennis Academy, and also began online homeschooling.

After her stepfather's death, Stephens and her family moved back to their hometown of Fresno where her grandparents and other members of her mother's family still lived. From then on, she split time living in both California and Florida.