- CaO stands for Calcium Oxide
- CaO stands for Central Applications Office (student placements in Irish universities)
- CaO stands for Chief Administrative Officer (corporate title)
- CaO stands for Conception Assistée par Ordinateur (French: Computer-Aided Design)
- CaO stands for County Administrative Officer
- CaO stands for Collectieve Arbeidsovereenkomst (Dutch)
- CaO stands for Chief Accounting Officer (job title)
- CaO stands for Chief Academic Officer
- CaO stands for County Assistance Office (Pennsylvania)
- CaO stands for Central Auditing Organization (Egypt)
- CaO stands for Control Applications of Optimization (conference)
- CaO stands for Civil Aviation Organisation (various locations)
- CaO stands for Critical Areas Ordinance (Washington)
Abbreviations And Their Meaning