Octa may refer to:
- Octa, Ohio
- Octa of Kent (6th century), early king of Kent
- Okta, a cloud cover over one eighth of the sky in weather reports
- octa, an Infrastructure-as-a-Service portal for Red Hat Enterprise Virtualization
OCTA is an abbreviation or acronym for:
- Office of the Chief Trade Adviser
- Orange County Transportation Authority
- Oregon-California Trails Association
- Oregon Cannabis Tax Act