Kari Martonen (born 13 March 1963) is a Finnish football manager and former player.
As a player, he played in total of 248 matches and scored 22 goals for HJK and FC Haka. After retiring as a player, he started working as a youth coach at his former club Haka and soon became the assistant manager under Olli Huttunen. In 2006, he became the assistant manager under Mika Lehkosuo at FC Honka.
In November 2009 as Ville Priha was sacked from JJK, Martonen took over as a head coach, signing a three-year contract with JJK.