| Abbreviation | Definition |
|---|---|
| INPR | Institute for National Policy Research |
| INR | Institute for Natural Resources |
| INRAE | Institut national de recherche pour l'agriculture, l'alimentation et l'environnement, |
| INSE | Institute for Natural Systems Engineering |
| INSEAD | INStitut Européen d'ADministration des affaires (European Institute of Business Administration) |
| INSET | Institute for Nano Science Engineering and Technology |
| INSI | International News Safety Institute |
| INSS | Institute for National Security |
| INSTE | Instituto Teológico por Extensión (Guatemala) [Spanish: Institute of Theology by Extension] |
| INT | Institute for Nuclear Theory |
| INT | Institute of Nuclear Theory |
| INTI | International New Town Institute |
| IOA | Institute Of Acoustics |
| IOA | Institute of Outdoor Advertising |
| IOA | Institute on Aging |
| IOB | Institute of Bankers |
| IOB | Institute of Banking |
| IOB | Institute of Bioinformatics |
| IOBD | Institute of Behavioral Design |
| IOBM | Institute of Builders Merchants |