| Abbreviation | Definition |
|---|---|
| NAFI | North American Family Institute |
| NAIA | North American Institute of Aviation |
| NAISE | Northwestern Argonne Institute of Science and Engineering |
| NAIT | Northern Alberta Institute of Technology |
| NAMII | National Additive Manufacturing Innovation Institute |
| NAOI | North American Outdoor Institute |
| NAPEI | National Association of Private Educations Institutes |
| NARI | National Ageing Research Institute |
| NARI | National Agricultural Research Institute |
| NARI | Nebraska Applied Research Institute |
| NASI | Native American Summer Institute |
| NATHM | Nepal Academy of Tourism and Hotel Management |
| NATI | North American Training Institute |
| NAYI | Nebraska Agricultural Youth Institute |
| NBBI | New Birth Bible Institute |
| NBBI | New Brunswick Bible Institute |
| NBCI | Newman Breastfeeding Clinic Institute |
| NBCI | North Branch Correctional Institution |
| NBEI | North Bengal Engineering Institute |
| NBFI | Non-Bank Financial Institution |