HN may refer to:
- Hacker News, a popular tech news site
- Hanoi, Vietnam
- Hawk Nelson, a Christian punk band
- Heavylift Cargo Airlines' IATA airline designator
- Heilbronn, a city in Germany
- HN, an abbreviation for Hell No!, a negative exclamation shouted when a less than pleasing event occurs
- Herceg Novi, a town in Montenegro
- Honduras, country code ISO 3166-1 alpha-2
- Hn., an abbreviation for Horn (instrument) in musical scores
- HN, the abbreviation for Hospitalman, a United States Navy Hospital Corpsman rate
- Hutchinson and Northern Railway
- Hyperdimension Neptunia, a game
- Hn., abbreviation for Hanım, a Turkish word for Mrs.
- HN, a numbering system for Royal Doulton Figurines named after employee Harry Nixon
- Hardware Node, Virtual Ethernet device concept
- .hn, Internet country code top-level domain (ccTLD) for Honduras
- , a two-letter combination used in some languages
- Reduction of /hn/ to /n/ in Old/Middle English
The Collaborative International Dictionary
HN \HN\ n. a colorless explosive liquid that is volatile, poisonous, and foul-smelling.
Syn: hydrazoic acid, azoimide.