Koa is a species of tree endemic to Hawaii.
Koa or KOA may also refer to:
- Guwa language, or Koa, an Australian language
- Kampgrounds of America, a franchise chain of North American campgrounds
- KCNC-TV, an American television station, which used the callsign KOA-TV from December 24, 1953 until August 1983
- KOA (AM), an American radio station
- KOA Corporation of Japan
- Koa people (Guwa), an Aboriginal Australian people
- IATA code KOA Kona International Airport, Hawaii
- Konami of America, the North American subsidiary of Konami, later known as Konami Corporation of America
- Koya language, or Koa, a language of India
- Kick Off Association, an organization for fans of the soccer simulation computer game Kick Off
- Kingdoms of Amalur: Reckoning, a 2012 video game