Asa may refer to:
In people:
- Asa (given name), a given name (including a list of persons with the name)
- Asa, god of the Kamba people ethnic group in Kenya
In geography:
- Asa, Iran, in South Khorasan Province
- Asa, Nigeria, in Kwara State
- Asa River (disambiguation), multiple rivers with the name
- American Samoa, or IOC country code ASA, an unincorporated territory of the United States
Other:
- Aspirin, or simply ASA, a drug used to treat aches, fever and inflammation
- Asa Shigure, character in the Shuffle! media franchise
- Asa (raga), Indian format of musical rules
- Ása, genitive of Æsir, the predominant group among the Norse gods
- Asa Station, Japanese railway station in San'yō-Onoda, Yamaguchi
- Asa, or naboot, a staff used in Egyptian stick fencing
- ASA physical status classification system, a system for assessing the fitness of patients before surgery
- ASA, a film speed rating system defined by the former American Standards Association