Jarkko Martikainen (born October 24, 1970 in East Germany) is known for singing, writing lyrics, and composing for the Finnish band, YUP. In addition to his musical career Martikainen has worked as a columnist, a producer, and a documentarist.

Martikainen has also illustrated his first solo album Mierolainen (2004) and YUP’s third album, Toppatakkeja ja Toledon terästä (1994).In 2005 Martikainen published a collection of short stories, Pitkät piikit ja muita tarinoita, which criticizes modern lifestyle and consumerism, etc.

In February 2008 his second written work, Yhdeksän teesiä was published. Yhdeksän teesiä includes also short stories, but this time in more poetic form. In September 2006, Jarkko’s second solo album Rakkaus was published.

After that he was voted for Best Solo Artist 2006. His first live album, Hyvää yötä ihmiset… nukkukaa hyvin, was released in September 2007.