HH may refer to:

Organizations

* Happy Hippie Foundation, a non-profit organization founded by Miley Cyrus * Hartmann House Preparatory School, an independent preparatory school in Harare, Zimbabwe * Heirs Holdings, a Nigerian conglomerate with diversified interests * Helly Hansen, a Norwegian brand specializing in clothing and gear for oceans and mountains * Heywood Hill, a bookshop in London

Science and technology

* Hh, a signalling molecule in Drosophila named for the Hedgehog signaling pathway * hh blood group, a rare blood type * Henderson–Hasselbalch equation, in biology and chemistry * Herbig–Haro object, in astronomy * Hitchhiker Program, a NASA program established in 1984 * Hodgkin–Huxley model, an electrical model of neurons * Microsoft Compiled HTML Help (hh.exe) * Hereditary haemochromatosis

Transportation

* HH (Court Street Shuttle) a defunct line on the New York City Subway from 1936 to 1946 * HH (Rockaway Shuttle), from 1962 to 1972 * HH Ferry route between Helsingborg, Sweden and Helsingør, Denmark * Air Hamburg, a German airline based in Hamburg (IATA code HH)

Other uses

*hh (digraph), in several languages * HH, a brassiere cup size * hh, an abbreviation for "hand (unit), hands high" when referring to the height of a horse * HH, short for Hand-Held, a term in film production among camera staff *HH, the production code for the 1967 ''Doctor Who'' serial ''The Moonbase'' * Hakainde Hichilema, Zambian politician * Hamburg, Germany (ISO 3166-2 code DE-HH) and HH ("Hansestadt Hamburg"), vehicle licence plate prefix * Happy Hour, a period of time (not necessarily one hour) when bars and restaurants offer discounts on food and/or drinks *Heil Hitler, a chant prevalent in Nazi Germany and neo-Nazi groups * His Highness, or Her Highness, a formal address * His Holiness, or Her Holiness, a formal address * Horrible Histories, media franchise *Hulk Hogan, American professional wrestler *Herbert Huncke, American Writer {{disambiguation