Unia, released on 25 May 2007, is the fifth full-length studio album by the power metal band Sonata Arctica, following the album Reckoning Night. The first single from the album was "Paid in Full", released on 27 April 2007. This is also the last album that features guitarist Jani Liimatainen, who was later replaced by Elias Viljanen after the album was released.

Sonata Arctica is a Finnish power metal band from the town of Kemi, Finland. Created as a hard rock band named Tricky Beans, they later changed to Tricky Means and finally to Sonata Arctica, when they shifted to power metal. The current lineup consists of drummer Tommy Portimo, lead singer Tony Kakko, keyboardist Henrik Klingenberg, guitarist Elias Viljanen and bassist Pasi Kauppinen. All the musicians of the band's history except Portimo also acted as backing vocalists.