HSA
- East African Safari Air
- HSA Bank
- HSA Foundation
- HSAS (disambiguation)
- Haiku Society of America
- Harry Stern Airport
- Harvard Student Agencies
- Hawker Siddeley
- Hayel Saeed Anam Group
- Health Sciences Authority
- Health Spending Account
- Health and Safety Authority
- Health savings account
- Healthcare Spending Account
- Heat stable antigen
- Hellenic Space Agency
- Heterogeneous System Architecture
- High Speed Amphibian
- Hmar Students' Association
- Homeland Security Act
- Host State Act (Switzerland)
- Human serum albumin
- Hunt Saboteurs Association
- Simplyhealth
- Stennis International Airport
- Sultanah Aminah Hospital
- The Harlem School of the Arts