ASW, a three-letter abbreviation, may refer to:

  • Air Southwest, a British airline
  • Ambrosia Software, a predominantly Macintosh software company.
  • Anti-submarine warfare
  • Artificial seawater
  • Aswan International Airport
  • All Star Wrestling, a professional wrestling promotion based in Liverpool, England
  • aSmallWorld, an online social network service
  • A Softer World, a webcomic
  • Arc System Works, a video game developer
  • Actual silver weight, a numismatic term
  • American School of Warsaw, an international school in Warsaw, Poland.
  • African ancestry in the southwestern United States, one of the populations of the International HapMap Project.