OLA
- OLA Girls Senior High School (Ho)
- OLA Girls Senior High School (Kenyasi)
- Official Languages Act 2003
- Oklahoma Library Association
- Online authorisation
- Ontario Lacrosse Association
- Ontario Legislative Assembly
- Ontario Library Association
- Open Learning Agency
- Operational-level agreement
- Oregon Library Association
- Oromo Liberation Army
- Our Lady of the Abandoned Parish Church (Marikina)
- Overland Airways
- Overlap–add method
- Transdev Germany
- United Nations Office of Legal Affairs
- WebSphere Optimized Local Adapters