AHA may refer to:
- AHA! A Hands-On Adventure, a children's museum in Lancaster, Ohio
- Alpha Hydroxy Acid
- Amateur Hockey Association
- American Heart Association
- American Hebrew Academy
- American Historical Association
- American Hockey Association (disambiguation)
- American Homebrewers Association
- American Hospital Association
- American Humane Association
- American Humanist Association
- Arabian Horse Association
- Association of Hispanic Arts
- Atlanta Housing Authority
- Atlantic Hockey Association
- Australian Hotels Association
- Autoimmune hemolytic anemia (more commonly abbreviated AIHA)
Aha may also refer to:
- Aha experience, (from German Aha-Erlebnis) an insight that manifests itself suddenly
- a-ha, Norwegian pop music band
- Aha (god), in ancient Egyptian theology
- Aha (spirit), a female spirit in Yakut myth who is the guardian of rivers
- One of two figures in the Book of Mormon:
- Aha (Book of Mormon), a Nephite soldier
- Ahah (Book of Mormon), a Jaredite
- Hor-Aha, Egyptian Pharaoh
- Aha ha, a species of wasp
- "Aha", an Egyptian phrase found on the Rhind Papyrus:
- used to indicate an unknown quantity
- a substitute for the variable letter x
- Aha !, poetry by Aleister Crowley
- AHA!, an information and education program in the Philippines
- Aha!, a 2007 Bangladeshi film
- "Aha!", a song by British singer Imogen Heap