OBA
- Ago-Oba
- Benin City Ring Road
- Oba (orisha)
- Oba (ruler)
- Oba Chandler
- Oba Island
- Oba Market
- Oba River
- Oba of Benin
- Oba, Anambra
- Oba, Ontario
- Oba-Igbomina
- Obba (disambiguation)
- Office Business Applications
- Oklahoma Bankers Association
- Oklahoma Bar Association
- Oklahoma Bible Academy
- On base average
- One Bermuda Alliance
- One Big Beautiful Bill Act
- Online Behavioral Advertising
- Only Boys Aloud
- Ontario Bar Association
- Openbare Bibliotheek Amsterdam
- Optical Brightening Agent
- Orange Beach, Alabama
- Ormiston Bolingbroke Academy
- Out-of-band agreement
- Output-based aid
- Oxygen Breathing Apparatus
- Tidore
- Ōba