45

45 may refer to:
 * 45 (number)
 * one of the years 45 BC, AD 45, 1945, 2045

Film

 * 45 (film), directed by Peter Coster (2009)
 * .45 (film), directed by Gary Lennon (2006)

Music

 * 45 (Jaguares album), 2008
 * 45 (Kino album), 1982
 * "45" (Bon Iver song), 2016
 * "45" (The Gaslight Anthem song), 2012
 * "45" (Shinedown song), 2003
 * "45" (Elvis Costello song), 2002
 * "Forty Five", a song by Karma to Burn from the album Appalachian Incantation, 2010
 * 45 rpm record or 45, a common form of vinyl single

Other uses

 * Donald Trump, the 45th President of the United States, with the nickname "45"
 * 45 (book), written by Bill Drummond
 * .45 caliber, a family of firearm cartridges
 * A nickname for a handgun chambered in .45 caliber, such as the M1911 pistol or Colt Single Action Army
 * .45 ACP, pistol cartridge
 * .45 Colt, revolver cartridge
 * Jacobite rising of 1745 or "The '45", in the United Kingdom
 * Forty-fives, a card game
 * 'The 45%', collective term used by Scottish independence campaigners (after ratio of support in 2014 referendum)
 * Fortyfive, a software development company
 * 45 Eugenia, a main-belt asteroid
 * Rover 45, a small family car