| Abbreviation | Definition |
|---|---|
| OWAF | One World Arts Foundation, Inc. |
| OWF | Ohio Works First |
| OWF | One World Foundation, Inc. |
| OWF | Oregon Wildlife Federation |
| OWL | Older Women's League |
| OWLS | Orphans Without Love or Shelter |
| OWLS | Outer Banks WildLife Shelter |
| OWT | Oregon Water Trust |
| OWWA | Ocracoke Working Watermen's Association |
| OWWA | OHIO Water Well Association |
| OXFAM | Oxford Committee for Famine Relief |
| OXFAM-GB | Oxford Committee for Famine Relief, Great Britain |
| OYA | Office for Young Adults |
| OYD | Organization for Youth and Development |
| OYD | Oxfordshire Young Diabetics |
| OYH | Ohio Youth Home |
| OYH | Open Your Heart |
| OYH | Optimist Youth Homes |
| OYH | Over Your Head |
| OYP | Orleans Young Players |