Mikaela Pauline Shiffrin (born March 13, 1995) is an American alpine skier. Shiffrin is the most decorated American alpine skier in World Championships history. She has the most World Cup wins of any alpine skier in history (men or women) and is the only one to have reached the milestone of 100 victories. She is a three-time Olympic gold medalist, four-time Olympic medalist, an eight-time World Championships gold medalist (including four titles in slalom), a six-time overall World Cup champion, and a nine-time winner of the World Cup slalom discipline title. Shiffrin, at 18 years and 345 days, became the youngest slalom gold medalist in Olympic history in 2014.

Shiffrin won her eighth career Alpine world championships gold medal on February 11, 2025, taking her overall tally to 15 medals from 18 career world championship races, and making Shiffrin the most successful skier in the modern era. She was named one of the 100 most influential people in the world by Time magazine in 2023.

Born in Vail, Colorado, Shiffrin is the second child of Eileen (née Condron) and Jeff Shiffrin, both originally from the Northeastern United States and former ski racers, her mother became a nationally prominent masters racer. Her paternal grandfather was Jewish. Shiffrin's father Jeff grew up in New Jersey and was an avid skier on weekends in Vermont with his family. As an undergraduate, he raced for Dartmouth College in New Hampshire. Her mother Eileen raced in high school in northwestern Massachusetts in the Berkshires, and her brother Taylor (born 1992) raced for the University of Denver.

When Mikaela was eight in 2003, the family moved to rural New Hampshire near Lyme, where her father, an anesthesiologist, worked at Dartmouth–Hitchcock Medical Center. After five years, he took a new job in Denver; Shiffrin's older brother Taylor was in high school at Burke Mountain Academy, a ski academy in northeastern Vermont, and stayed in the east. Shiffrin also attended middle school at Burke but went with her parents to Colorado before returning to Burke.

From a young age, Mikaela had strong results in major competitions. In March 2010, at age 14, she won both the slalom and giant slalom (GS) at the Topolino Games in Italy, against skiers from 40 nations. The following winter, now meeting the FIS minimum age requirement of 15 years, she won a Nor-Am Cup super combined race in December 2010 at Panorama, British Columbia, only the eighth FIS-level race in which she had competed. Shiffrin followed it up with three podiums in her next three Nor-Am races: runner-up in a super-G, third in a GS, and victory in a slalom. Weeks later, she won a pair of Nor-Am slalom races held at Sunday River, Maine. A month later, Shiffrin took the slalom bronze medal at the FIS Junior World Ski Championships held at Crans-Montana, Switzerland (after having been down with a stomach virus the day before).

In February 2020, her father unexpectedly died in an accident. Since 2021, Shiffrin has been in a relationship with the Norwegian World Cup alpine ski racer Aleksander Aamodt Kilde. On April 4, 2024, the couple announced their engagement.

In May 2025, Shiffrin joined the ownership group for National Women's Soccer League expansion club Denver Summit FC. In June 2025, she received an honorary Doctor of Humane Letters degree from Dartmouth College.

Shiffrin made her World Cup debut on March 11, 2011, in giant slalom at Špindlerův Mlýn in the Czech Republic. In early April, just a few weeks after her 16th birthday, she won the slalom title at the US National Championships at Winter Park, Colorado, and became the youngest American ski racer to claim a national alpine crown.