5W

5W or 5-W may refer to:

Units of measurement

 * 5°W, or 5th meridian west, a line of longitude
 * 5 watts
 * 5 weeks
 * 5 wins, abbreviated in a win–loss record (pitching)

Science, technology and transportation

 * 5W, IATA code of Wizz Air Abu Dhabi
 * 5w, a viscosity grade of motor oil
 * I-5W, westbound Interstate 5
 * Interstate 5 in California
 * AD-5W, a version of the Douglas A-1 Skyraider
 * 5W, then IATA code for Astraeus Airlines which operated from 2002 until 2011

Other uses

 * Five Ws: Who?, What?, When?, Where?, and Why?
 * "Which Was What Was Wanted", an alternative to Q.E.D.
 * 5W Public Relations, a public relations agency
 * 5W, production code for the 1982 Doctor Who serial Four to Doomsday