| Acronym | Definition |
|---|
| HAP | Hazardous Air Pollutant |
| HAP | Hydroxyapatite |
| HAP | Health Alliance Plan (Michigan) |
| HAP | Hydrocarbures Aromatiques Polycycliques (French: Polycyclic Aromatic Hydrocarbons) |
| HAP | Housing Assistance Payment (US Housing & Urban Development Program) |
| HAP | Hot Air Pencil (various companies) |
| HAP | Hospital-Acquired Pneumonia |
| HAP | Hook-Associated Protein |
| HAP | Hearing Aid Program (various organizations) |
| HAP | High Availability Package |
| HAP | Health Administration Press (American College of Healthcare Executives) |
| HAP | Housing Authority of Portland (Portland, OR) |
| HAP | Histidine Acid Phosphatase |
| HAP | Hypoxia-Activated Prodrug (cancer) |
| HAP | Humanitarian Accountability Partnership International (Geneva, Switzerland; est. 2003) |
| HAP | Hourly Analysis Program |
| HAP | High Assurance Platform |
| HAP | Humanitarian Action Plan |
| HAP | Hague Appeal for Peace |
| HAP | High Altitude Platform |
| HAP | Health Advocacy Program (various locations) |
| HAP | Homeownership Assistance Program (Florida) |
| HAP | Host Access Protocol |
| HAP | Higher Achievement Program (education) |
| HAP | High Achievers Program (various locations) |
| HAP | Human Anatomy and Physiology |
| HAP | Hospital and Healthsystem Association of Pennsylvania (also seen as HHAP) |
| HAP | Highly Abundant Protein (immunology) |
| HAP | Hitachi Automotive Products (various locations) |
| HAP | Hazard Abatement Plan (US FEMA) |
| HAP | High Average Power |
| HAP | Healthy Aging Partnership (Puget Sound, WA) |
| HAP | Holiday Assistance Program (various organizations) |
| HAP | Healthcare Assistance Program (various locations) |
| HAP | High Accident Potential |
| HAP | Hillside Agricultural Project (Jamaica) |
| HAP | Home-owners' Assistance Program |
| HAP | Hospital Advantage Plan (AARP) |
| HAP | High Altitude Parachutist |
| HAP | Hierarchical Analytical Protocol |
| HAP | Hai Asia Pacific (Sri Lanka) |
| HAP | Hardware Architecture Plan |