Mikke Leinonen (born January 14, 1992) is a Finnish former athlete who specialized in Nordic combined, a winter sport that consists of cross-country skiing and ski jumping. Born in Lahti, Finland, he represented the sports club Lahden Hiihtoseura during his competitive career.
Leinonen competed at the international level on the FIS (International Ski Federation) circuit from 2010 until his retirement in 2016. He was a member of the Finnish national team and represented his country at several major international tournaments. His most prominent appearance was at the 2014 Winter Olympics in Sochi, Russia, where he competed in the individual normal hill/10 km and individual large hill/10 km events, finishing 40th and 42nd, respectively.
In addition to the Olympic Games, Leinonen participated in the FIS Nordic World Ski Championships 2013 held in Val di Fiemme, Italy. He also made frequent appearances in the FIS Nordic Combined World Cup, making his debut in March 2011 in his hometown of Lahti. His best individual result in a World Cup event was a 19th-place finish.
Leinonen announced his retirement from professional Nordic combined in 2016 at the age of 24, citing a lack of sufficient motivation to continue competing at the elite international level.