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