Big Bang Theory most commonly refers to: The Big Bang, a cosmological model of the universe The Big Bang Theory, an American TV sitcom It may also refer to: Music Big Bang Theory (song), Barenaked Ladies (2007) themesong to the U.S. TV sitcom, see The Big Bang Theory#Theme song Big Bang Theory (Styx album) (2005) Big Bang Theory (Harem Scarem album) (1998) Other uses "The Big Bang Theory" (Family Guy), a 2011 episode of the TV series See also Big Bang (disambiguation)