An affair is a sexual relationship, romantic friendship, or passionate attachment between two people without the attached person's significant other knowing.

Affair may also refer to:

• Foreign affairs,
  • as in Foreign policy
  • or Foreign Affairs (publication)
• Internal affairs, as in law enforcement
• Political affairs, see political scandal
• Affair (album), a 1988 album by Cherrelle
• Affairs (album), a 1980 album by Elliott Murphy
• Affair (film), a 2010 Indonesian film
• "Affair" (Big Love), a 2006 television episode
• "Affairs" (Shameless), a 2004 television episode

• The Affair (disambiguation)
• All pages with titles containing Affair