| Acronym | Definition |
|---|
| IIN | Institute for Integrative Nutrition (New York) |
| IIN | Is It Normal |
| IIN | Istituto Italiano di Navigazione (Italian: Italian Institute of Navigation) |
| IIN | International Institute for Nanotechnology (est. 2000; Northwestern University; Ilinois) |
| IIN | Instituto Interamericano del Niño (Inter-American Children's Institute) |
| IIN | Intelligent Information Network |
| IIN | Internet Intelligent Network |
| IIN | Imagery Information Need |
| IIN | Instituto de Investigacion Nutricional (Peru) |
| IIN | Installation Instructions |
| IIN | Intelligent Information Network (Cisco) |
| IIN | Issuer Identification Number (credit cards) |
| IIN | Impedance Inverter Network (microwave theory) |
| IIN | Indigenous Information Network (Kenya) |
| IIN | IBM Information Network |
| IIN | International Identification Number |
| IIN | Interferometric Intensity Noise |
| IIN | Incidental Installation Material |