BL

• Boys' love, a Japanese term for fiction featuring romantic relationships between male characters
• BL Publishing, a division of the wargames manufacturing company, Games Workshop
• Boston Legal, a US legal comedy-drama

• Balmer Lawrie, an Indian government-owned business
• Boys' Latin School of Maryland
• British Leyland, a former UK vehicle manufacturing company
• Pacific Airlines (IATA code BL), a low-cost airline

• Bachelor of Laws (B.L.), an undergraduate degree in law
• Barrister-at-Law, in Ireland and Northern Ireland

• BL postcode area, UK, covering Bolton and Bury in Greater Manchester
• Bakerloo line, a London Underground line
• Banja Luka, a city in Bosnia and Herzegovina
• Bannan line, a Taipei Metro line, code BL
• Saint Barthélemy [ISO country code BL], a Caribbean overseas collectivity of France
• Basel-Landschaft (Basel-Country), a canton of Switzerland
• Province of Belluno, Italy (car-license plate abbreviation BL)
• Blue Line (MBTA), a Boston subway line, code BL
• Bolivia (FIPS Pub 10-4 and obsolete NATO digram BL), a central South American country
• Brazil, LOC MARC code

Mathematics and computing

• BL (logic), basic fuzzy logic
• BL register, the low byte of an X86 16-bit BX register

Other uses in science and technology

• Designation of unfiltered black light fluorescent tubes
• British term for breech-loading ordinance

• Ы, Yery or Yeru, a letter in the Cyrillic script, which resembles lowercase B and L written together (bl)
• Bill of lading, a receipt issued by a shipping carrier
• Bhutia-Lepcha, an Indian ethnic group
• BL, the production code of the second generation Mazda3/Axela
• Aceh (vehicle registration prefix BL)