Stephan Sieben (b. 1977) is a Danish guitarist and composer. He is co-leader of ILK bands Angel, Big Bombastic Collective (nominee of a Danish music award 2007 for the album Diamonds), and Sekten who was honored with a Danish music award in 2006 for the album Annnars är det tyst. He also co-leads in Babakarej and Rhododendron String Band.
Since 2000 he has been working and collaborating with musicians and bands like Bordeline Ensemble, Chris Speed, Dánjal, Elektronavn, Kostcirkeln, Paal Nilssen-Love, Peter Friis Nielsen, T.S Høeg, Trio Trash a.o.
His music and way of playing is strongly attached to the tradition of free improvisation and abstract playing but he is also influenced by metal, rock, pop and countrymusic.