| Acronym | Definition |
|---|
| WAO | World Allergy Organization |
| WAO | Women's Aid Organisation (Malaysia) |
| WAO | Wet Air Oxidation |
| WAO | Wild Animal Orphanage |
| WAO | Work Area Outlet |
| WAO | World Autism Organisation |
| WAO | Workshop on Accelerator Operations |
| WAO | Women's American ORT |
| WAO | Wet Op Arbeidsongeschiktheid (legislation, Netherlands) |
| WAO | World Association for Orphans and Abandoned Children (various locations) |
| WAO | Weapons Assignment Officer |
| WAO | Weighted Average of Individual Offsets |
| WAO | Washington Area Office |
| WAO | Weeks After Order |
| WAO | We Are One, Inc. |