Alexei Konstantinovich Yagudin (Russian: Алексей Константинович Ягудин, IPA: [ɐlʲɪˈksʲeɪ̯ kənstɐnʲˈtʲinəvʲɪt͡ɕ ɪ̯ɪˈɡudʲɪn] ^ⓘ; 18 March 1980) is a Russian former competitive figure skater. He is the 2002 Olympic champion, a four-time World champion (1998, 1999, 2000, 2002), a three-time European champion (1998, 1999, 2002), a two-time Grand Prix Final champion (1998–1999, 2001–2002), the 1996 World Junior champion, and a two-time World Professional champion (1998, 2002).

Yagudin is the only skater (all disciplines included) to have achieved a Golden Slam, a victory in all major championships (Olympic Games, World Championships, European Championships, Grand Prix assignments, Grand Prix Final) in the same season (2001–2002). In 2003, Yagudin was awarded with the Order of Merit for the Fatherland IV degree of the Russian Federation. In 2017, he was inducted into the World Figure Skating Hall of Fame.

After his retirement from eligible skating, Yagudin has toured as a professional skater and appeared as a show host, an actor and a figure skating commentator for Russian television networks. In 2019, he opened the Figure Skating Center Alexei Yagudin in Minsk, Belarus where he coaches.

Alexei Yagudin was born on 18 March 1980 in Leningrad, Russian SFSR, Soviet Union. When Yagudin was four, his father moved to Germany, severing all contact with his wife and son. His parents would officially divorce when he was 12. He graduated from the Lesgaft National State University of Physical Education, Sport and Health.

Yagudin was introduced to skating at age four by his mother, Zoya, who saw the activity as a way to improve his health. He learned all his double jumps before age ten, the five triple jumps before age twelve, and the triple Axel jump before he turned thirteen. His first coach was Alexander Mayorov, and then he was introduced to the famous Russian coach Alexei Mishin when Mayorov moved to Sweden in 1992. Yagudin trained in Mishin's group from 1992 to 1998. He began competing at the international level in 1994, and won the 1996 World Junior Championships. The famous rivalry with fellow Russian skater Evgeni Plushenko began when they trained in Mishin's group, and intensified after Yagudin left.

In 1997, Yagudin competed in the World Championships for the first time and won a bronze medal.

In 1998, Yagudin led a Russian sweep of the medals at the 1998 European Championships with Evgeni Plushenko in second and Alexander Abt in third. Later that year, he competed at the 1998 Nagano Winter Olympics despite a severe case of pneumonia, and finished in 5th place. A month later, he won the 1998 World Championships. He became the first Russian single skater from the post-Soviet era to win the World title. He was the second-youngest male World Champion at the age of 18 years and 15 days, 6 days older than Donald McPherson in 1963. About two months after the event, Yagudin left Mishin and joined Tatiana Tarasova, who would coach him until his retirement in 2003.

In the 1998–99 season, Yagudin won eleven out of the thirteen competitions in which he participated, which included the defeat of Kurt Browning in the World Professional Championships, and winning the Grand Prix Final. At the 2000 European Championships, he finished ahead of both Plushenko and former Olympic champion Alexei Urmanov to win his second continental title. He successfully defended his world title against Plushenko at the 2000 World Championships in Nice, France.