45

45 may refer to:

• 45 (number), the natural number following 44 and preceding 46
• one of the years 45 BC, AD 45, 1945, 2045

• 45 (2009 film), a short psychological thriller
• 45 (2025 film), a Kannada-language action fantasy film
• .45 (film), a 2006 American independent thriller film

• 45 rpm record or 45, a common form of vinyl single
• 45 (Jaguares album), 2008
• 45 (Kino album), 1982
• "45" (Elvis Costello song), 2002
• "45" (The Gaslight Anthem song), 2012
• "45" (Shinedown song), 2003
• "45", a song by Bon Iver from the 2016 album 22, A Million
• "Forty Five", a song by Karma to Burn from the 2010 album Appalachian Incantation

• 45 (book), by Bill Drummond, 2000
• Forty-five, a Doctor Who anthology audio drama

• .45, the diameter in inches of several 11 mm caliber firearm cartridges
  • Colt .45 caliber, the M1911 pistol
  • .45 calibre Colt Single Action Army revolver
• Donald Trump, the 45th and 47th president of the United States
• Jacobite rising of 1745, or "The '45", in Scotland and England
• Forty-fives, a card game
• Fortyfive, a software development company
• Rover 45, a small family car (1999–2005)