NPI may refer to:
- Numbering plan indicator
- New Politics Initiative
- New product introduction
- Negative polarity item (Linguistics)
- National Policy Institute
- National Provider Identifier
- Network Printer Interface, an ID number for HP printers/print servers
- Nickel pig iron
- No pun intended
- Nonpublic Personal Information (Gramm–Leach–Bliley Act)
- Northwest Progressive Institute
- Norwegian Polar Institute
- Nottingham Prognostic Index
- NPI abbreviation for Nationaal Pop Instituut, the Dutch Rock & Pop Institute
- National pollutant inventory
- Narcissistic Personality Inventory, a standard personality test for evaluating self-centredness
- Nordic Patent Institute
- NP-intermediate, a complexity class in computational complexity theory