SNI
- National Information Service (Brazil)
- National Standardization Agency
- Scripps Networks Interactive
- Seicho-no-Ie
- Server Name Indication
- Shelter Now International
- Showtime Networks Inc.
- Siemens Nixdorf Informationssysteme
- Sistema Nacional de Investigadores
- Société Nationale d'Investissement
- Soviet Naval Infantry
- Sports Network Incorporated
- Substitution nucleophilic internal
- Swedish Standard Industrial Classification
- Swiss Nanoscience Institute