NCI can stand for:
- National Cancer Institute
- National Captioning Institute
- Nordic Centre in India
- National College of Ireland
- Native Communications Inc - Aboriginal Public Broadcaster in Manitoba, Canada.
- National Coastwatch Institution, UK voluntary coastwatch organisation
- North Coast Institute of TAFE
- In chemistry, Negative Chemical Ionization
- Noarlunga Centre Interchange in Adelaide, Australia
- NCI Group, an American manufacturing company
nCi can stand for:
- Nanocurie