Ha

Ha may refer to:

• Health authority, a former type of administrative organisation of the NHS in England and Wales
• Hells Angels Motorcycle Club
• Highways Agency (renamed Highways England, now National Highways), UK government body maintaining England's major roads
• Homelessness Australia, peak body organisation for homeless people and services
• Homosexuals Anonymous an ex-gay program for dealing with unwanted same-sex attractions
• Hong Kong Housing Authority
• Hospital Authority of Hong Kong

• Ha (Doseone album), 2005
• Ha (Talvin Singh album), 2002
• Ha! (Killing Joke album), 1982
• "Ha" (21 Savage song)
• "Ha" (Juvenile song)
• Ha! (TV channel), an American all-comedy TV channel
• Hamar Arbeiderblad, a Norwegian newspaper
• Human Action, a book by the Austrian economist Ludwig von Mises
• The Jim Henson Company, formerly known as ha!

• A laugh
• Ha (Javanese) (ꦲ), a letter in the Javanese script
• Ha (kana), in syllabic Japanese script
• ه (hāʾ), ح (ḥāʾ), or خ (ḫāʾ), Arabic letters
• హ (ha), a Telugu letter
• Ha language, the language of the Ha people in eastern Africa
• Hausa language, ISO 639-1 code HA

• Ha, Bhutan
• Hå Municipality, a municipality in Rogaland county, Norway
• Ha Gorge, Greece
• HA postcode area, a group of English postal districts in north-west London
• Henan, a province of China (Guobiao abbreviation HA)

• Hahnium, an element now called Dubnium
• Hyaluronan (Hyaluronic acid), a carbohydrate structure
• Hydroxylapatite, a mineral

• Hyperandrogenic anovulation, also called polycystic ovary syndrome
• Health anxiety (HA) or hypochondriasis (hypochondria)
• Hemagglutinin (influenza) (HA), an antigenic glycoprotein from Influenza viruses
• Hemagglutination assay, a measurement of viruses or bacteria

• Hartree, an atomic unit of energy
• Hectare (ha), a unit of area
• Hectoampere, a unit of electric current

• ha (function prefix) (half), a prefix for some trigonometric functions in mathematics
• Hallstatt culture, an archaeological culture
• High availability, systems design and implementation with a view to maximising service
• Hour angle, in astronomy, one of the coordinates of the equatorial coordinate system
• H_a, or alternative hypothesis, in statistical testing
• H-alpha (Hα), a deep-red visible spectral line of the hydrogen atom

• Ha (Chinese surname) (哈), found in the Hundred Family Surnames
• Ha (Korean surname) (하, 河 or 夏)
• Hà, Vietnamese surname
• Xia (surname) (夏), romanized as Ha in Cantonese, Korean and Vietnamese pronunciation

• British Rail Class 71, a locomotive (classified type HA under the Southern Region's pre-TOPS scheme)
• Hawaiian Airlines, former IATA designator HA
• Highways Agency (now National Highways), UK government body maintaining England's major roads
• Hungary (aircraft registration prefix HA)

• Ha (mythology)
• Ha, one of deities Heng and Ha
• Ha people, a Tanzanian people
• Hospitalman Apprentice, a U.S. Navy rank