HM or hm may refer to:
Arts and entertainment
- HM (magazine), a Christian hard rock magazine
Businesses, groups, organizations
- H&M, a Swedish clothing company
- Hindustan Motors, an automobile manufacturer of India
- Air Seychelles (IATA airline code <code>HM</code>)
- HM Transport, a bus company in the Philippines
People
- Henry Molaison, aka Patient H.M., a man with anterograde amnesia
- His or Her Majesty, a form of address for various monarchs
- Home Minister, an interior minister
- Hospital corpsman, in the United States Navy
- Sisters of the Holy Humility of Mary's postnominal initials
Other uses
- Heard Island and McDonald Islands (ISO 3166 digram and FIPS PUB 10-4 territory code <code>HM</code>)
- .hm, the Internet country code top-level domain ostensibly for the above
- Hectometre (<code>hm</code>), an SI unit of length
- Hindley–Milner type system, in mathematics
- "Half marathon" athletics abbreviation in road racing