| Abbreviation | Definition |
|---|---|
| OFN | Ourlads Football Network |
| OHA | Old Hobartians Association football club |
| OM | Out Match |
| OMFL | Ontario Minor Football League |
| ONTFL | Ottawa Nepean Touch Football League (Canada) |
| OS | Onside (or Off side) |
| OSFA | Old Scholars Football Association |
| OTFC | Old Tiffinians Football Club |
| OTHF | Over The Hill Football |
| OVFL | Ohio Valley Football League |
| OVFL | Ontario Varsity Football League |
| OXFC | Old Xaverians Football Club |
| OYF | Okinawa Youth Football |
| PAFA | Palatine Amateur Football Association |
| PAFC | Port Adelaide Football Club |
| PANTS | Players Are Not Trying Sufficiently |
| PAPA | Pedispheroidal Amateur Prognostication Association |
| PDFA | Pune District Football Association |
| PDFC | Port District Football Club |
| PDFL | Panther Developmental Football League |