| OBC | Other Backward Classes |
| OCR | Optical Character Recognition |
| OECD | Organisation for Economic Cooperation and Development |
| OGL | Open General License |
| OIL | Oil India Limited |
| OK | All Correct |
| ONGC | Oil and Natural Gas Corporation |
| OOP | Object Oriented Programme |
| OPEC | Organisation of Petroleum Exporting Countries |
| OSCAR | Orbiting Satellite Carrying Amateur Radio |
| OTR | Operational Turn Around |
| PAN | Permanent Account Number |
| PCI | Press Council of India |
| PCS | Provincial Civil Services |
| PERDA | Pension Fund Regulatory and Development Authority |
| Ph. D | Doctor of Philosophy |
| Ph.D. | Doctor of Philosophy (Philosophiae Doctor) |
| PIL | Public Interest Litigation |
| PIN | Postal Index Number |
| PLO | Palestine Liberation Organisation |
| PM | Post Meridian/Prime Minister |
| POTA | Prevention of Terrorism Act |
| PRO | Public Relations Officer |
| PSLV | Polar Satellite Launch Vehicle |
| PTI | Press Trust of India |
| PTO | Please Turn Over |
| PVC | Poly Vinyl Chloride/Paramvir Chakra |
| PVSM | Param Vishisht Seva Medal |
| PWD | Public Works Department; |
| PWG | People's War Group |
