NCI can stand for:

• National Cancer Institute
• Nordic Centre in India
• Nuclear Cities Initiative, see NCI website
• National College of Ireland
• Native Communications Inc - Aboriginal Public Broadcaster in Manitoba, Canada.
• Non-Ceramic Insulator a.k.a Polymer Insulator
• National Coastwatch Institution, UK voluntary coastwatch organisation, see NCI website

nCi can stand for:

• nano Curie