| Acronym | Definition |
|---|
| OHA | Office of Hawaiian Affairs |
| OHA | Office of Hearings and Appeals (US federal government) |
| OHA | Ontario Hockey Association (Canada) |
| OHA | Open Handset Alliance |
| OHA | Ontario Hospital Association |
| OHA | Ohio Hospital Association |
| OHA | Otis Historical Archives (est. 1968; National Museum of Health and Medicine) |
| OHA | Oral History Association |
| OHA | Overseas Housing Allowance |
| OHA | Oakland Housing Authority (Oakland, CA) |
| OHA | Oral Health America |
| OHA | Office of Health Affairs |
| OHA | Omaha Housing Authority |
| OHA | Office of Historic Alexandria (Alexandria, VA) |
| OHA | Oncology Hematology Associates (Newburgh, IN) |
| OHA | Orkney Housing Association (UK) |
| OHA | Odorous House Ant (insect) |
| OHA | Oakland Heritage Alliance (Oakland, CA) |
| OHA | Orlando Housing Authority |
| OHA | Ontario Horticultural Association (Canada) |
| OHA | Oak Hill Academy |
| OHA | Ontario Homeopathic Association (Canada) |
| OHA | Oklahoma Heritage Association |
| OHA | Oral Hypoglycaemic Agent |
| OHA | Old Harveians' Association (UK; alumni group) |
| OHA | Ontario Health Association (Canada) |
| OHA | Outdoor Household Articles |
| OHA | Occupational Health Assessment (NIOSH) |
| OHA | Operations Hazard Analysis |
| OHA | Ocala Housing Authority |
| OHA | Octavia Hill Association, Inc. |
| OHA | Organization for Humanitarian Assistance |
| OHA | O'Hara Hall (University of Scranton) |
| OHA | Operating/Operational Hazard Analysis |
| OHA | Ohio Halfway House Association (now Ohio Community Corrections Association) |