HH

HH may refer to:

Organizations

 * HH Electronics, a British amplifier manufacturer
 * 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
 * HH Tunnel a proposed series of tunnels between Helsingborg and Helsingør
 * 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 "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
 * Habbo, online community formerly known as Habbo Hotel
 * 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
 * Heath Hitler, White supremacist
 * 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
 * HH, the name for the former mascot of the electronics/appliances store H. H. Gregg