ONSA
| Acronym | Definition |
|---|---|
| ONSA | Ohio Nursing Students' Association |
| ONSA | Oklahoma Nursing Student Association |
| ONSA | Office of the National Science Advisor (Canada) |
| ONSA | Organization for Nucleotide Sequencing and Analysis |
| ONSA | Oregon Neighborhood Store Association |
| ONSA | Operasionele Navorsingsvereniging Van Suid-Afrika (Afrikaans: Operations Research Society of South Africa) |
| ONSA | Office of the National Security Adviser (various nations) |