HM or hm may refer to:

Arts and entertainment

* HM (magazine), ''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

* 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 the above * Hectometre, hm, an SI unit of length * Henry Molaison, aka Patient H.M., a man with anterograde amnesia * His or Her Majesty, a form of address for various monarchs * Hindley–Milner type system, in mathematics * Hospital corpsman, in the United States Navy * Sisters of the Holy Humility of Mary's postnominal initials {{disambiguation