"Bad Girlfriend" is the second single released by Theory of a Deadman from their album Scars & Souvenirs. It was released to radio and for downloads on May 14, 2008. In the U.S., "Bad Girlfriend" was the most added song on rock radio and grew quickly in plays and downloads, therefore making a debut on the Bubbling Under Hot 100 Singles chart. It debuted at #89 on the Canadian Hot 100, and quickly arose to peak at #1. It is currently their most successful single in the U.S, with "So Happy", the single before it, being their previous most successful, making Scars & Souvenirs their most successful album as well. The song was co-written by Christine Connolly. The song is Theory's second big breakthrough from this album, carrying the band to the top of the Mainstream Rock Charts within 14 weeks. It is also the band's second song to reach the top 20 of the Modern Rock Chart, so far peaking at #8. So far, it been their fourth top 10 hit on the Mainstream Rock Charts. Almost a year and a half after the release of "Bad Girlfriend" to rock radio, it is being released to mainstream radio in December, as Sirius Hits 1 added the song in November 2008.