ERO
- EROS (disambiguation)
- Early Release Observations
- Edge recombination operator
- Education Review Office (New Zealand)
- Electoral registration officer
- Emergency Regulations Ordinance
- Emergency response officers
- Ero (spider)
- Eros (disambiguation)
- Eugenics Record Office
- European Conference of Postal and Telecommunications Administrations
- ICFTU European Regional Organisation
- IRS e-file
- James Webb Space Telescope
- The Legend of Ero of Armenteira
- U.S. Immigration and Customs Enforcement
- Uzi