| Acronym | Definition |
|---|
| HAA | Histiocytosis Association of America (Pitman, NJ) |
| HAA | Houston Arts Alliance |
| HAA | Harvard Alumni Association |
| HAA | High Altitude Airship |
| HAA | HIV/AIDS Administration (District of Columbia) |
| HAA | Haloacetic Acid |
| HAA | Houston Apartment Association |
| HAA | Hospice Association of America (Washington, DC) |
| HAA | Heavy Anti-Aircraft |
| HAA | Height Above Airport (aviation) |
| HAA | Herpetological Association of Africa |
| HAA | Heterocyclic Aromatic Amine |
| HAA | Hrvatska Akreditacijska Agencija (Slovenian: Croatian Accreditation Agency; Croatia) |
| HAA | Home Automation Association |
| HAA | Hispanic Agenda for Action (HHS BHPR US government) |
| HAA | Holy Angels Academy (Buffalo, NY) |
| HAA | Hawaii Aquaculture Association |
| HAA | Hinsdale Adventist Academy (Hinsdale, IL) |
| HAA | Hired Assassin Agency |
| HAA | Hellenic Army Aviation |
| HAA | Heat Activated Adhesive |
| HAA | Hispanics Across America (New York, New York) |
| HAA | Hormonally Active Agent |
| HAA | Heavy Anti-aircraft Artillery |
| HAA | hemoglobin-associated acetaldehyde (laboratory test indicative of heavy alcohol use) |
| HAA | Holstein Association of America |
| HAA | Haris Al Afaq (Dubai, UAE) |
| HAA | Horatio Alger Association of Distinguished Americans |
| HAA | High Activity Aircraft (military flying exercises) |
| HAA | Heartland Alliance of America |
| HAA | Hold At Airborne |
| HAA | Humanitarian Assistance for Afghanistan |
| HAA | High Acceleration Assist (Mode) |
| HAA | Havyaka Association of Americas (New Jersey) |
| HAA | Humans Against Acronyms |
| HAA | Home and Away (Australian TV show) |