Nu or NU may refer to:
- Nu (letter), a letter in the Greek alphabet: lowercase ν, uppercase Ν
- Nu (kana), the Japanese characters ぬ and ヌ
- Nu (mythology), the male form of the Egyptian goddess Naunet
- Nu (Chrono Trigger), a fictional species from the video game Chrono Trigger
- N.U. (film), 1948 documentary film directed by Michelangelo Antonioni
- .nu, the Internet top-level domain for Niue
- Nu people, a Chinese ethnic group
- Nu river or Salween River
- U Nu or Mr. Nu, a former Burmese prime minister
- Mr. Nu, a fictional character from the novel Hitman: Enemy Within
- Nǀu language, a moribund Tuu (Khoisan) language spoken by the Nǁnǂe people in South Africa
- NuMachine computer architecture developed at MIT in the late 1970s that included the NuBus.
- Nu (programming language), an interpreted object-oriented programming language
- Nu Gundam, in the anime Mobile Suit Gundam: Char's Counterattack
- Nu, a Yiddish interjection meaning "well?" or "so?"
- a Chinese term for crossbow, as in the chu-ko-nu or repeating crossbow
- Niagara University, a Roman Catholic university in Niagara County, New York
- Northeastern University, an American research university in Boston, Massachusetts
- Northwest University, a private university in Kirkland, Washington
- Northwestern University, an American research institution in Evanston, Illinois
- Norwich University, a private American military and traditional university in Northfield, Vermont
- University of Nebraska–Lincoln
- Argentinean National Universities
- Nanjing University, a national university in China
- Naresuan University, a public university in Phitsanulok, Thailand
- Nile University, a private research university in Egypt
- National University (Philippines), a private, non-sectarian university in Manila, Philippines
- NU Bulldogs, the intercollegiate athletic program of the above school
- Nkumba University, a private university near Entebbe, Uganda
- Nirma University, a private university in Ahmedabad, India
In other abbreviations:
- Northern Union (NU), early name of the Rugby Football League
- Nunavut (NU), the largest and newest territory in the territories of Canada
- Nahdatul Ulama (NU), an Islamic group in Indonesia
- Nusselt number (Nu), a dimensionless heat transfer ratio
- Poisson's ratio, a dimensionless ratio relating strain on element along one axis to the strain in an orthogonal axis, is symbolized by the Greek Nu
- Nucellar embryony (Nu+), a form of seed reproduction that occurs in certain plant species
- Bhutanese ngultrum (Nu.), Bhutan's official currency
- Northeast Utilities, a gas and electric company in the northeastern United States
- Japan Transocean Air IATA airline designator
- Nicaragua NATO country code
- Niue ISO 3166 country code
- Nu Metal, a fusion genre of Heavy Metal.
- Nu Jazz, a fusion genre of Jazz.
- Nu-Disco, a Dance music genre.
- Nu folk, a fusion genre of Folk.
- Nu Gaze, a fusion genre of Shoe Gaze.
- Nu prog, a subgenre of Progressive Rock.