NBL may refer to:
- Any of several basketball leagues named National Basketball League
- National Basketball League (1898–1904) (United States) (defunct), the first professional men's basketball league in the world
- National Basketball League (Australasia), the pre-eminent professional men's basketball league in Australasia
- National Basketball League (Bulgaria)
- National Basketball League (Canada) 1993-94 (defunct)
- National Basketball League (China), a professional men's basketball minor league in China
- National Basketball League (Czech Republic)
- National Basketball League (Indonesia)
- National Basketball League (Japan)
- National Basketball League (Lithuania), a semi-professional men's basketball minor league in Lithuania
- National Basketball League (Malaysia)
- National Basketball League (New Zealand)
- National Basketball League of Canada
- National Basketball League (United Kingdom) 1972–2003 (defunct)
- National Basketball League (United States) 1937–49 (defunct)
- Namibia Breweries Limited
- National Bicycle League (United States)
- National Blackbelt League, the world's largest and most prestigious sport karate league tournament
- National Book League (United Kingdom)
- National Bowling League (United States) (defunct)
- n-Butyllithium, an organic compound.
- Neutral Buoyancy Laboratory, an astronaut training facility at NASA's Johnson Space Center
- New Brunswick Laboratory
- Noble Energy, an oil and natural gas exploration and production company listed on the New York Stock Exchange with the ticker symbol NBL
- Noni B Limited, one of Australia's most respected fashion retailers listed on the Australian Stock Exchange with the ticker symbol NBL
- North Bay League, now part of the North Coast Section of the California Interscholastic Federation (CIF)
- North Berwick Law, a volcanic plug in East Lothian, Scotland
- North British Locomotive Company