PCO
- Indonesia
- PCO Imaging
- PCOS (disambiguation)
- Parliamentary Counsel Office (disambiguation)
- Pendrell Corporation
- Penguin Cafe Orchestra
- Pennsylvania College of Optometry
- Philippines
- Pickleball in Canada
- Pierre Carl Ouellet
- Pleasure Craft Operator Card
- Polycystic ovary syndrome
- Posterior capsular opacification
- Precinct Committee Officer
- Presidential Communication Office
- Presidential Communications Office
- Private cable operator
- Privy Council Office (Canada)
- Privy Council Office (United Kingdom)
- Professional conference organiser
- Prospective Commanding Officer
- Provisional Constitutional Order
- Public Carriage Office
- Public call office
- Punta Colorada Airstrip
- Workers' Cause Party
- Workers' Communist Party of Canada