Insomnium is a Finnish melodic death metal band from Joensuu, Finland. They are influenced by doom metal, playing songs about sorrow, death, loss, and mourning. They also incorporate elements of nordic / norse folk music and symphonic music into their sound. Their name refers to a category of nightmares/visions in Medieval Europe.

Since their inception, Insomnium have steadily evolved their style of music. Their melodies are highly melancholic, and their overall sound is much darker. The band's lyrics tend to be influenced (and occasionally taken) from classic poets like Friedrich Hölderlin, Edgar Allan Poe, Charles Baudelaire, Francis William Bourdillon and Finnish classic Eino Leino and other literature.