ONS may stand for:
- Object naming service
- Office for NATO Standardization
- Office National de la Statistique (Mauritania, ons.mr)
- Office National des Statistiques de l'Algérie (ons.dz)
- Office for National Statistics (UK, ons.gov.uk)
- Offshore Northern Seas Foundation
- Onboard navigation system
- Oncology Nursing Society (ons.org)
- One night stand
- Operador Nacional do Sistema Elétrico (Brazil, ons.org.br)
- Oriental Numismatic Society