HL

HL may refer to:

Business

• Hangars Liquides, an electronic music label
• Hargreaves Lansdown, a British investment company
• Hitachi-LG Data Storage, an optical disc drive manufacturer
• Hogan Lovells, an international law firm
• Houlihan Lokey, an international investment bank
• Hovedstadens Lokalbaner, a Danish local railway company

Linguistics

• ⟨hl⟩, a Latin-script digraph
• Reduction of /hl/ to /l/ in Old/Middle English
• Voiceless alveolar lateral fricative, a sound sometimes represented as ⟨hl⟩

Science and medicine

• Half-life, in nuclear physics
• Hectolitre, a unit of volume
• Hodgkin's lymphoma, a highly treatable hematological malignancy ("blood cancer")
• Hydrogen line, a spectral line
• HL gas, a mixture of sulfur mustard and lewisite

Other uses

• Croatian Labourists – Labour Party (Croatian: Hrvatski laburisti - Stranka rada), a political party in Croatia
• Half-Life (series), a video game series
  • Half-Life (video game), the first game in that series
• Headline, a text indicating the nature of the article below it
• Hessdalen light, an unexplained light seen Norway
• Hit list (disambiguation)
• Horseland, an online community and virtual game
• Hotline, a telecommunications link
• House of Lords, the upper house of the Parliament of the United Kingdom
• Hypotenuse Leg, a postulate of geometry
• Higher Level, a level of course difficulty in the International Baccalaureate Diploma Programme
• Hospitality Lawyer, a hospitality resource website founded by Stephen Barth