NB or Nb may refer to:
Arts and entertainment
- NB Global, a British investment company
- New Balance, a shoe company
- Nigerian Breweries, a beverage company
- Sterling Airlines, a defunct Danish airline (IATA designator)
- National bank (disambiguation) several banks
Science and technology
- NB class, steam locomotives
- Boeing NB, a 1923 training aircraft
- Naive Bayes classifier, in statistics
- Neuroblastoma, a type of cancer
- Niobium, a chemical element with symbol Nb
- Nominal Bore or Nominal Pipe Size
- Nanobarn (nb), a unit of cross-sectional area
- NB MX-5 Miata, the second generation of the Mazda MX-5
- Bokmål, written standard for Norwegian language (ISO 639-1 code NB))
- Narrowboat ship prefix
- 牛B (niúbī), a common word in Mandarin Chinese profanity, It means 'badass' or 'freaking awesome'
- Non-binary, a gender identity
- Nota bene, a Latin phrase meaning "note well"
- All pages beginning with "NB"
- All pages with a title containing NB