Fifteen or 15 may refer to:

• 15 (number)
• one of the years 15 BC, AD 15, 1915, 2015

• Fifteen (band), a punk rock band

• 15 (Buckcherry album), 2005
• 15 (Ani Lorak album), 2007
• 15 (Phatfish album), 2008
• 15 (Tuki album), 2025
• 15 (mixtape), a 2018 mixtape by Bhad Bhabie
• Fifteen (Green River Ordinance album), 2016
• Fifteen (The Wailin' Jennys album), 2017
• Fifteen, a 2012 album by Colin James

• "Fifteen" (song), a 2008 song by Taylor Swift
• "Fifteen", a song by Harry Belafonte from the album Love Is a Gentle Thing
• "15", a song by Rilo Kiley from the album Under the Blacklight
• "15", a song by Marilyn Manson from the album The High End of Low

• 15 (film), a 2003 Singaporean film
• Fifteen (TV series), international release name of Hillside, a Canadian-American teen drama
• "Fifteen" (Runaways), an episode of Runaways
• Fifteen (novel), a 1956 juvenile fiction novel by Beverly Cleary

• Fifteen, Ohio, a community in the United States
• Fifteen puzzle, a sliding puzzle
• Fifteen (confection), a sweet traybake confection from Northern Ireland
• The Fifteen, the Jacobite rising of 1715 where the House of Stuart attempted to regain the throne of the United Kingdom.
• 15 years old is the age of Quinceañera
• 15 (programmer), creator of the deep learning speech synthesis application 15.ai

• Fifteenth (disambiguation)
• Line 15, various metro lines
• Route 15, various highways and public transport routes
• 15 rating (disambiguation)