| O'er | Over (As in, "O'er yonder lay the green fields of home.") 
| Others |
| OER | Object Event Repository
| Others |
| OER | Ocean Exploration and Research
| Others |
| OER | Octet Encoding Rules
| Others |
| OER | Offensive Efficiency Rating
| Others |
| OER | Office of Energy Resources
| Others |
| OER | Office of Environmental Remediation
| Others |
| OER | Office of Extramural Research
| Others |
| OER | Officer Evaluation Report
| Others |
| OER | Oil Extract Rate
| Others |
| OER | Open Education Resources
| Others |
| OER | Open Educational Resources
| Others |
| OER | Open Ended Response
| Others |
| OER | Operating Expense Ratio
| Others |
| OER | Operational Electronic Intelligence (ELINT) Requirements
| Others |
| OER | Operational Excelence Review
| Others |
| OER | Optical & Electronic Research
| Others |
| OER | Optical & Electronic Research, Incorporated
| Others |
| OER | Optimized Edge Router
| Others |
| OER | Ora de Educatie Rutiera
| Others |
| OER | Order Execution Result
| Others |
| OER | Original Equipment Reproduction
| Others |
| OER | Ornskoodsvik, Sweden
| Others |
| OER | Owner Equivalent Rent
| Others |
| OER | Owners Equivalent Rent
| Others |
| OER | Oxygen Enhancement Ratio
| Others |
| OER | Oxygen Evolution Reaction
| Others |