| Acronym | Definition |
|---|
| OPO | Openbaar Primair Onderwijs (Dutch: Public Primary Education) |
| OPO | Open Purchase Order (procurement) |
| OPO | Organ Procurement Organization |
| OPO | Office of Procurement Operations (US DHS) |
| OPO | Ophthalmic and Physiological Optics (publication; Wiley) |
| OPO | Osaka Philharmonic Orchestra (Japan) |
| OPO | Oracle Power Objects |
| OPO | Optical Parametric Oscillator(s) |
| OPO | Office of the Permanent Observer (Inter-Parliamentary Union) |
| OPO | Overnight Pulse Oximetry (pulmonary disease) |
| OPO | Porto, Portugal - Porto (Airport Code) |
| OPO | Office of Public Outreach (NASA) |
| OPO | Observation Post Officer |
| OPO | Other People's Opinions |
| OPO | One Person Operated |
| OPO | Operations Order |
| OPO | Opposite Polarity |
| OPO | Office of Provincial Outreach |
| OPO | OPNAV Principal Official |
| OPO | Ovamboland People's Organization |
| OPO | Office of Personnel Operations |
| OPO | Orbiter Project Office |
| OPO | Psion OPL Output (executable file extension) |
| OPO | Outpatient Observation |
| OPO | One Production Only (acting contracts) |
| OPO | Operational Performance Objectives |
| OPO | Orbiting Planetary Observatory |
| OPO | Oil Pressure Out |
| OPO | Over-Pressure Operations |
| OPO | Ohio Peace Officer |