Viktor An (Russian: Виктор Ан; born Ahn Hyun-soo (Korean: 안현수) on November 23, 1985), is a South Korean-born Russian short-track speed skating coach and retired short-track speed skater. With a total of eight Olympic medals, six gold and two bronze, he is the only short track speed skater in Olympic history to win gold in every distance, and the first to win a medal in every distance at a single Games. He has the most Olympic gold medals in the sport, three of which he won in the 2006 Winter Olympics and the other three in the 2014 Winter Olympics. Considered to be the greatest short track speed skater of all time, he is a six-time overall World champion (2003–2007, 2014), two-time overall World Cup winner (2003–04, 2005–06), and the 2014 European champion. He holds the most overall titles at the World Short Track Speed Skating Championships, and is the only male short track skater to win five consecutive world titles.
In 2008, Ahn suffered a knee injury and could not regain his health by the time the national qualifiers for Vancouver 2010 came around. His recovery being slow and his South Korean local team dissolved in 2010, Ahn, aiming for his second Olympics, became a Russian citizen the next year and began racing for the Russian team. After winning gold in Sochi, Ahn explained his reasons for joining the Russian team saying, "I wanted to train in the best possible environment and I proved my decision was not wrong." As expected, a gold-winning athlete leaving the national team caused public uproar in South Korea. However, it was aimed not at Ahn, but at the country's skating union. Most South Korean fans in a poll said they understood his decision. Ahn continued his skating career in his adopted nation until 2019 and declared his retirement in April 2020.