Big Bang Theory
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
 "The History of Everything", AKA the theme from ''The Big Bang Theory", a song by 2007 Barenaked Ladies
 Big Bang Theory (Billy Bang album) (2000)
 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)