Larsen Alan Jensen (born September 1, 1985 in Bakersfield, California) is an American swimmer, who graduated from the University of Southern California in May 2007. In the 2003 World Championship, Larsen received a silver medal in the 800 meters freestyle, his first medal at the international level. He won the 500yd and 1650yd freestyle at the 2006 Men's NCAA Championships.
He competed in the 2004 Summer Olympics, winning silver in the 1500 meter freestyle race as well as competing in the 400 meter freestyle, where he finished fourth. At the Montreal 2005 World Aquatics Championships (long course), he won a silver medal in the 800 meters and the 1,500 meters freestyle. Jensen competed in the 2008 Summer Olympics in Beijing where he won the Bronze medal in the 400 meter freestyle, and also placed fifth in the 1500 m freestyle.