IAS
- Climate Change Act 2008
- IAS Cargo Airlines
- IAS Limited
- IAS machine
- IEEE Industry Applications Society
- Iași International Airport
- Immunisation Awareness Society
- Indian Administrative Service
- Indicated airspeed
- Institut aéronautique et spatial
- Institute for Advanced Study
- Institute for Advanced Study (disambiguation)
- Institute for Advanced Study at University of Minnesota
- Institute for Anarchist Studies
- Institute of Advanced Study (Durham)
- Institute of Aerospace Sciences
- Institute of Agricultural Sciences, Banaras Hindu University
- Instituto Ayrton Senna
- Insulin autoimmune syndrome
- Integral Ad Science
- Interactive Application System
- Intergovernmental Affairs Secretariat (Canada)
- Internal Audit Service (European Commission)
- Internal anal sphincter
- International AIDS Society
- International Accounting Standards
- International Association of Scientologists
- International Association of Sufism
- International Automated Systems
- International Financial Reporting Standards
- Internet Authentication Service
- Iowa Archeological Society
- Iranian Arachnological Society
- Izquierda Asturiana
- Oracle Application Server