HM

HM or hm may refer to:

Arts and entertainment

 * HM (magazine), a Christian hard rock magazine
 * Hidden Machine, a type of item in Pokémon

Businesses

 * H&M, a Swedish clothing company
 * Hindustan Motors, an automobile manufacturer of India
 * Air Seychelles (IATA airline code)

Other uses

 * Hectometre, hm, an SI unit of length
 * Henry Molaison, aka Patient H.M., a man with anterograde amnesia
 * Hindley–Milner type system, in mathematics
 * Hospital corpsman, in the United States Navy
 * His Majesty or Her Majesty, a form of address for monarch of the United Kingdom and Commonwealth realm.
 * Sisters of the Holy Humility of Mary's postnominal initials
 * Heard Island and McDonald Islands (ISO 3166 digram and FIPS PUB 10-4 territory code)
 * .hm, the Internet country code top-level domain ostensibly for Heard Island and McDonald Islands