IAS may refer to:

• Institute for Advanced Study, in Princeton, New Jersey, United States
• Image Analysis & Stereology, the official journal of the International Society for Stereology & Image Analysis.
• Iowa Archeological Society, United States
• Iranian Arachnological Society, for the study of arachnids in Iran
• International AIDS Society, an association of HIV/AIDS professionals
• Institute of Agricultural Sciences, Banaras Hindu University, in India
• Institute for Advanced Study at University of Minnesota in Minneapolis, Minnesota
• Institute of Advanced Study (Durham) in Durham, North East England
• IEEE Industry Applications Society
• International Association of Sedimentologists

• Indian Administrative Service, the Indian administrative civil service
• Intergovernmental Affairs Secretariat (Canada)
• Internal Audit Service (European Commission)

• International Accounting Standards
• Investment Analysts Society of Southern Africa
• various numbered International Financial Reporting Standards

• International Association of Scientologists
• International Association of Sufism

• Institute for Anarchist Studies
• Izquierda Asturiana, a political party in Spain
• Immunisation Awareness Society, a New Zealand anti-vaccination group
• International Aviation and Shipping emissions, specifically greenhouse gas emissions arising from those sectors (the term also used in the United Kingdom Climate Change Act 2008)

• Indicated airspeed
• Institute of Aerospace Sciences, in the United States
• Institut aéronautique et spatial, in France
• Iași International Airport, IATA designation for the airport in Iași, Romania
• IAS Cargo Airlines, a British airline

• IAS machine, the first electronic computer built at the Institute for Advanced Study
• Interactive Application System, a DEC PDP-11 operating system
• Internet Application Server, alternate name for Oracle Application Server
• Internet Authentication Service, a component of Windows Server

• Instituto Ayrton Senna, an NGO in Brasil
• Insulin autoimmune syndrome, a rare cause of reversible autoimmune hypoglycemia
• Integral Ad Science, an American technology company that analyzes the value of digital advertisements
• International American School of Warsaw, a preK–12 school in Poland
• International Automated Systems, an American company
• IAS Limited an Australian-based gambling company
• Internal anal sphincter, human anatomy

• Institute for Advanced Study (disambiguation)

This disambiguation page lists articles associated with the title IAS.
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