| Abbreviation | Definition |
|---|---|
| OMAC | Olney Margolies Athletic Center |
| OMGAA | Osseo Maple Grove Athletic Association (youth athletics; Maple Grove, MN) |
| OOAA | Okotoks Oilers Athletic Association |
| OPAA | Orange Park Athletic Association |
| OPRA | Outdoor Programs Recreation and Athletics |
| OPRA | Outdoors Program Recreational Athletics |
| OPRA | Outdoors Program/Recreational Athletics |
| OTPTAT | Occupational Therapy Physical Therapy and Athletic Trainers |
| OUA | Ontario University Athletics |
| OUAA | Ontario University Athletic Association |
| OVAC | Ohio Valley Athletic Conference |
| OVAC | Ojai Valley Athletic Club |
| OVERCOME | Optimism, Validus, Extreme, Reach, Calm, Obstacle, Make, and Eager. |
| OVERCOME | Optimism, Validus, Extreme, Reach, Calm, Obstacle, Make, and Eager. |
| OWAC | Ohio Wesleyan Athletic Council |
| OYAA | Olentangy Youth Athletic Association |
| PAA | Pasadena Athletic Association |
| PAA | Peninsula Athletic Association |
| PAA | Pittsburgh Athletic Association |
| PAAC | Pacific Avenue Athletic Complex |