Iñaki Lejarreta Errasti (1 September 1983 – 16 December 2012) was a Spanish mountain biker. He was a junior world champion in 2001, and national mountain bike champion in 2007. He competed in the cross-country cycling at the 2008 Beijing Olympics, and was professionally part of the Orbea cycling team. In 2012, Lejarreta was killed in a crash while training when his cycle was struck by a car. He was 29.

His father Ismael and his uncle Marino (winner of the 1982 Vuelta a España) were also professional cyclists.