Kevin Ray Martin (born July 31, 1966), nicknamed "the Old Bear" and "K-Mart", is a Canadian retired curler originally from Lougheed, Alberta and residing in Edmonton. He is an Olympic, World and four-time Canadian champion and a member of the World Curling Hall of Fame. He is considered by many commentators and former and current curlers to be the greatest curler of all time. He is also known for his rivalries with Randy Ferbey/David Nedohin, the best Alberta provincial rivalry ever as the two teams were generally regarded the best in the world from 2002 to 2006; his rivalry with Jeff Stoughton, perhaps the most famous all prairies rivalry ever which spanned over 2 decades from 1991 to 2014; with Glenn Howard from 2007 to 2014, perhaps the best two team rivalry in Canadian curling history, and his rivalry with Sweden's Peja Lindholm from 1997 to 2006, perhaps the best ever men's Canada-Europe rivalry.

Over his 30-year curling career, he won four Briers, a gold medal at the 2010 Winter Olympics, and one world championship. He went to a total of three Winter Olympics and four World Championships, and won a total of two Olympic medals and three World Championship medals. He won 15 Grand Slam titles on the World Curling Tour (the media count 18, including three Players' Championships won prior to its inclusion as a Grand Slam event), which includes a record eight Players' Championship titles. Over the course of his career, his teams won around $2 million. He was the first skip to win a "career Grand Slam," winning a title in each Grand Slam event, after he won the Players' Championship Grand Slam event in April 2005. Martin also holds the record for the most Olympic victories, with 20 total wins at the Olympics.

During his career, Martin also served as a major influence in the development of the sport of curling, establishing the competitive tier in the sport and setting the groundwork for the management of curling teams and the creation of high-level competitive curling events. He is also known for contributing to the growth of curling, long known as a recreational and participant-based sport, as a spectator sport. Martin retired from competitive curling in 2014. In 2019, Martin was named the greatest Canadian male skip in history in a TSN poll of broadcasters, reporters and top curlers.

In 2024, he was named as a member of the Order of Canada.

Martin began curling when he was six years old. He took up the sport because his father was the vice president of his local curling club. Martin first came on the curling scene in 1985 when his Alberta team of Richard Feeney, Dan Petryk and Michael Berger won the 1985 Canadian Junior Championship in their first year together as a team. The rink (a group of players) finished the round robin in second place, with a win–loss record of 7–4, behind Prince Edward Island's Kent Scales. This forced them into a semifinal against the third place Quebec rink, skipped by Steve Gagnon. They beat Quebec 5–4, earning a spot in the final against Prince Edward Island which they won with a score of 6–3. After winning the championship, he accompanied the Canadian team as an alternate at the 1985 World Junior Curling Championships.

By winning the 1985 Canadian junior championship, the team qualified for the following season's (1986) World Juniors. The team went undefeated through the round robin and won their semifinal match against Sweden. However, in the final, they came up short, losing 7–6 to the Scottish team skipped by David Aitken.

Five years out of the World Junior Championships, Martin had formed a new team and won his first provincial championship. This qualified him and his team of Kevin Park, Dan Petryk and Don Bartlett for the 1991 Labatt Brier. At the 1991 Brier, Martin finished the round robin with an 8–3 win–loss record, tying Saskatchewan for first place. Martin knocked off British Columbia in the semifinal, and then beat Saskatchewan (skipped by Randy Woytowich) with a score of 8–4 in the final. The rink was then off to the 1991 Canada Safeway World Curling Championships in Winnipeg. Martin turned the tables, going undefeated through the round robin. After beating Norway's Eigil Ramsfjell in the semifinal, Martin's team lost in the final, losing to Scotland's David Smith with a score of 2–7.

His 1991 Brier victory also earned him a spot at the 1992 Winter Olympics, where curling was just a demonstration sport at the time. Martin won all three of his round robin games before losing the semifinal to Switzerland with a score of 4–8 and losing to the United States with a score of 2–9 in the bronze medal match.