| Abbreviation | Definition |
|---|---|
| OBIRDC | Operation Blessing International Relief and Development Corporation |
| OBS | Overbrook School for the Blind |
| OBVC | Operation Black Vote Canada |
| OC | Organizing Committee |
| OC | Other Contributors |
| OCA | Occupational Chaplains of America |
| OCA | Organization of Chinese Americans |
| OCASI | Ontario Council of Agencies Serving Immigrants |
| OCASP | Orange County Active Single Parents |
| OCAW | Ontario Captive Animal Watch |
| OCC | Operation Christmas Child |
| OCCA | Oregon Coast Council for the Arts |
| OCCA | Ottawa Child Care Association |
| OCCB | OASIS Certificate and Competency Board, Inc. |
| OCDC | Ocean City Development Corporation |
| OCDE | Ohio Commons for Digital Education |
| OCEAN | Ocean Conservation through Education, Awareness, and Networking |
| OCF | Obsessive-Compulsive Foundation |
| OCF | Olympic Credit Fund |
| OCF | Oncology Children's Foundation |