CIRA
- CIRA-FM
- COSPAR international reference atmosphere
- Canadian Internet Registration Authority
- Central Illinois Regional Airport
- Centre International de Recherches sur l'Anarchisme (CIRA)
- Client Initiated Remote Access
- Continuity Irish Republican Army
- Cooperative Institute for Research in the Atmosphere
- Italian Aerospace Research Centre
- S. 2611
- Yale University Center for Interdisciplinary Research on AIDS (CIRA)