HM

HM may refer to:
* Heavy metals, higher atomic weight metallic elements
* Horace Mann School, private school in New York City
* "Hannah Montana", a popular Disney Channel TV show
* Haunted Mansion, a dark ride attraction in several Disney theme parks
* HM (patient), pseudonym of a man with anterograde amnesia (also written H.M.)
* HM (magazine), a Christian Hard rock magazine
* H&M, or Hennes & Mauritz, a Swedish clothing company
* Hindley-Milner, a type system
* Hospital Corpsman, in the United States Navy
* Fender HM Strat, a superstrat electric guitar
* His/Her Majesty, a form of address for a monarch and his/her consort
* Hidden Machine, in the video game series Pokémon
* Air Seychelles: International Air Transport Association (IATA) code
* Heard Island and McDonald Islands: ISO 3166 digram and FIPS PUB 10-4 territory code
* The academic area of Hospitality management studies
* Hindustan Motors, an automobile manufacturer of Indian origin
* Harvest Moon (series), a series of farming simulation video games.
* HM, an abbreviation of the surname, Horn-Muller

hm can signify:
* hectometre, an SI unit of length