NK may refer to:
Businesses
- Imerys, a French mining multinational (Euronext ticker:<code>NK</code>)
- Nordiska Kompaniet, a Swedish department store
- Northrup-King Seed Company, U.S.
- Spirit Airlines, U.S. (IATA:<code>NK</code>)
- NK.pl, a Polish social network (2006–2021)
Organisations
- Neturei Karta, a group of anti-zionist orthodox Jews
- Nippon Kaiji Kyokai, a ship classification society
- NK (), a name suffix for Croatian and Slovenian football clubs
Places
- North Korea, a country in Asia
- Nagorno-Karabakh Republic, a de facto state (1991–2023)
- Nikšić, Montenegro (license plate:<code>NK</code>)
- North Kingstown, Rhode Island, U.S.
- North Kingstown High School
- Nasik Road railway station (station code: NK), Maharashtra, India
Other uses
- NK (singer), a Ukrainian singer
- Naik (military rank), in certain South Asian armies
- Natural killer cell, in medicine
- Neue Kerze ('new candle'; nk), original name for the photometric unit the candela
- Norwegian krone, a currency
- Normal Country (, NK), a Polish right-wing political party
