Theory of a Deadman (abbreviated as Theory) is a Canadian rock band from Delta, British Columbia. Formed in 2001, the band is currently signed to Roadrunner Records as well as 604 Records. The band also includes traits of other music styles, such as country and acoustic, as well as their post-grunge and alternative rock base. They have had a total of eight top 10 hits on the US Billboard Hot Mainstream Rock Tracks chart, including three No. 1 hits, "Bad Girlfriend", "Lowlife" and "Rx (Medicate)".