NS as an abbreviation can mean:

In geography:

  • Negeri Sembilan, one of the fourteen states in Malaysia
  • Novi Sad, a city in Serbia (license plate code)
  • Nova Scotia, as the official Canadian postal abbreviation for the province

In government and politics:

  • Nasjonal Samling, a 1930s Norwegian national socialist political party
  • National service, a name for the conscription system of some militaries
  • Nazism, also known as "National Socialism" in Germany, the ideology held by, amongst many other political parties, the National Socialist German Workers Party
  • New Serbia (Нова Србија or Nova Srbija), a moderate nationalist political party in Serbia
  • New Slovenia (also known as Nova Slovenija - Krscanski Ljudska Stranka), a right-of-centre political party in Slovenia
  • People's Party, a political party in the Republic of Montenegro

In commerce:

  • National Semiconductor (also known as "Natsemi"), an American integrated circuit design and manufacturing company
  • Nederlandse Spoorwegen, the main public transport railway company in the Netherlands
  • Norfolk Southern Railway, a major Class I railroad in the United States, owned by the Norfolk Southern Corporation
  • Norfolk Southern Railway (former), the final name of a railroad running in Virginia and North Carolina before its acquisition by the Southern Railway in 1974

In computing and computer gaming:

  • Name server, a computer server that implements a name service protocol
    • NS record, a DNS record type
  • Namespace (computer science), an abstract container used in computing
  • Natural Selection (computer game), a mod for the game Half-life
  • NetStorm, an RTS published in 1997 by Activision
  • NEXTSTEP, an object-oriented, multitasking operating system by NeXT, as well as a prefix for certain system-provided classes in the operating system, such as "NSString"
  • ns (simulator) (or "ns-2"), a popular open source network simulator
  • Jennifer Government: NationStates, a web-based simulation game

In literature:

  • New Spring (known to fans as "NS"), a 1999 anthology edited by Robert Silverberg and derivative 2004 novella by Robert Jordan
  • NS-series robots from the book I, Robot

In science and history:

  • New Style (as "N.S."), indicating either a date in the Julian Calendar with the start of year adjusted to 1 January or a date in the Gregorian Calendar (see Old Style and New Style dates)
  • Nanosecond (abbreviated "ns"), a measure of time
  • Normal saline, a solution of sodium chloride used in intravenous drips (see Saline (medicine))
  • Nanostructure
  • Neutron star, a star formed from the collapsed remnant of a massive star
  • No significant difference, when differences between categories are smaller than the amount of error/noise in the data
  • Nervous system, the system of neurons that coordinates the actions of an organism

In other areas:

  • a ship prefix for civilian ship names meaning "Nuclear Ship"
  • a code for "non-smoking" designating that tobacco smoking is not permitted
  • in medicine, normal saline
  • Narcissistic supply