Liam Killeen (born 12 April 1982), is a British professional mountain biker. He represented England in cross country racing at the Commonwealth Games in 2002 where he came 3rd, and became Commonwealth Champion in 2006. He has won the British Mountain Biking National Champion over five consecutive years; 2008, 2009, 2010, 2011 and 2012. He competed for Great Britain at the 2004 and 2008 Summer Olympics and was chosen as the sole male cross-country rider for the British team for the London Games in 2012.