OEP may refer to:
- Object Engineering Process
- Occurrence Exceedance Probability, a risk curve used in catastrophe modeling
- Octaethylporphyrin, a synthetic porphyrin
- Office for Environmental Protection, UK organisation to be created by the Environment Bill and as of July 2021 existing in an interim state
- Office of Emergency Preparedness, U.S. Executive Branch organization abolished in 1973 and responsibilities divided among several organizations
- Office of Emergency Planning, emergency planning organisation within Ireland's Dept. of Defence
- One Equity Partners, the private equity affiliate of JPMorgan Chase
- Open Educational Practices
- Open Energy Platform, a project providing database infrastructure for open energy system models
- Open Enrollment Period, a period of time in which individuals may enroll in or change their health insurance plans.
- Optometric Extension Program
- Országos Egészségbiztosítási Pénztár, the publicly funded health service organization of Hungary
- Oxfordshire Economic Partnership
