| Abbreviation | Definition |
|---|---|
| HPA | Hollywood Post Alliance |
| HPOA | Hollywood Property Owners Alliance |
| HPTA | Hanover Parent Teacher Alliance |
| HQA | Hospital Quality Alliance |
| HRA | Humane Rescue Alliance |
| HRAU | Human Rights Alliance of Uzbekistan |
| HRBA | Historic Religious Buildings Alliance |
| HRIA | Hot Rod Industry Alliance |
| HSDA | Healthcare Supplier Diversity Alliance |
| HSDA | Handicapped Scuba Diving Alliance |
| HSEA | Health Systems Engineering Alliance |
| HSIA | Halogenated Solvents Industry Alliance |
| HSTA | Hindustan Sea Turtle Alliance |
| HTA | Health Transformation Alliance |
| HTA | Heterogeneous Technology Alliance |
| HTRA | Human Trafficking Rescue Alliance |
| HTRA | Humboldt Trinity Recreation Alliance |
| HVAA | Hudson Valley Agency Alliance |
| HWTA | Hotel Windermere Tenants Alliance |
| IAAA | International Air Ambulance Alliance |