OPC
- Bundesamt für Verfassungsschutz
- Heritage-class cutter
- Huntsville, Ontario
- O-Pee-Chee
- OPC Foundation
- Obama Presidential Center
- Ocean Prediction Center
- Office of Policy Coordination
- Office of the Parliamentary Counsel (United Kingdom)
- Office of the Privacy Commissioner of Canada
- Oligodendrocyte precursor cell
- Oligomeric proanthocyanidin
- Online Party of Canada
- Ontario Police College
- Oodua Peoples Congress
- Opel Performance Center
- Open Packaging Conventions
- Open Platform Communications
- Optical proximity correction
- Optimized Power Control
- Organic photoconductor
- Organisation for the Prevention of Blindness
- Oropharyngeal cancer
- Orthodox Presbyterian Church
- Ottawa People’s Commission
- Overseas Press Club
- Portland cement
- Progressive Conservative Party of Ontario
- Supervised injection site
- Surcharge (payment systems)
- Tivoli Software