NB, Nb, or nb may refer to:
Arts and entertainment
- N.B. (album), an album by Natasha Bedingfield
- NB (TV programme), a Scottish arts television programme that aired 1989–1997
Businesses
- NB Global Monthly Income Fund, a British investment company
- New Balance, a shoe company
- Niesenbahn, a funicular railway in Switzerland
- Nigerian Breweries, a beverage company
- Sterling Airlines, a defunct Danish airline (IATA designator)
- National bank (disambiguation) several banks
Language
- Nota bene, often abbreviated as NB or n.b., a Latin phrase meaning "note well"
- nb, ISO 639-1 code for Bokmål, the written standard of the Norwegian language
- <span lang="zh" dir="ltr">牛屄</span> (niúbī), a common word in Mandarin Chinese profanity
Places
- New Brunswick, a province of Canada, (postal abbreviation: NB)
- Nebraska, US, (former postal abbreviation: NB; changed to NE)
Science and technology
- Niobium, symbol Nb, a chemical element
- NB class, Australian steam locomotives
- Boeing NB, a 1923 training aircraft
- Naive Bayes classifier, in statistics
- Neuroblastoma, a type of cancer
- Nominal bore or nominal pipe size, a set of standard sizes for pipes
- Nanobarn (nb), a unit of cross-sectional area
- Mazda MX-5 (NB), the second generation of the Mazda MX-5
- NB (programming language), an intermediate-stage language known as "New B" that evolved from the "B" language and then further evolved into the "C" language
Other uses
- Narrowboat ship prefix
- National Battlefield, a protected area in the United States
- No-ball in cricket
- Non-binary, a term used by people who identify as neither male nor female