Hef or HEF may refer to:
- Hugh Hefner (born 1926), an American magazine publisher, founder and Chief Creative Officer of Playboy Enterprises
- High-energy fuel, a theoretic type of boron-based aircraft fuel
- High Explosive Fragmentation, a type of ammunition or ordnance
- Manassas Airport, a public-use airport located in Manassas, Virginia, United States
- Norwegian Humanist Association (Norwegian: Human-Etisk Forbund), currently one of the largest Humanist associations in the world