Jarkko Martikainen (born 24 October 1970 in Greifswald, GDR) is a Finnish singer, songwriter and member of the rock band YUP. In addition to his musical career, Martikainen has worked as a columnist, a record producer and a documentary filmmaker. Martikainen has also illustrated his first solo-album Mierolainen (2004) and YUP's third album, Toppatakkeja ja Toledon terästä (1994).
Martikainen has a very versatile and distinct voice.