| Acronym | Definition |
|---|
| OCO | Office of Community Outreach (various schools) |
| OCO | Orbiting Carbon Observatory |
| OCO | Old Cornish (linguistics) |
| OCO | Oracle Connector for Outlook |
| OCO | Overseas Contingency Operations |
| OCO | Open-Close-Open |
| OCO | Object Code Only |
| OCO | Organic Certification Organization (organic foods; Japan) |
| OCO | Ostrobothnian Chamber Orchestra (Finland) |
| OCO | Office of Climate Observation (NOAA) |
| OCO | Operating Capital Outlay |
| OCO | Offensive Cyberspace Operation |
| OCO | Online Channel Optimization |
| OCO | Orange County Open (golf tournament; California) |
| OCO | Oort Cloud Object |
| OCO | Office of Central Operations |
| OCO | Overall Control Office |
| OCO | One Cancels the Order (banking, foreign exchange) |
| OCO | Operational Contracting Officer |
| OCO | Office of Civilian Operations |
| OCO | Off-Load Control Officer |
| OCO | Operating and Control Organization |
| OCO | Operational Capabilities Objective |
| OCO | Office, Chief Ordnance |
| OCO | Oklahoma Community Orchestra |
| OCO | Office of the Credit Ombudsman |
| OCO | Oahu Civic Orchestra (Hawaii) |
| OCO | Olathe Community Orchestra (Olathe, KS) |
| OCO | Oakland Civic Orchestra (Oakland, CA) |
| OCO | Optimal Cycle Ordering |