IAAS can refer to the following:
Organisations International Association for Astronomical Studies, a youth astronomy and aerospace research group based out of Denver, Colorado with a 40+ year history of success in the youth STEM fields.
Incorporated Association of Architects and Surveyors, former name of the British professional body Association of Building Engineers International Association for Shell and Spatial Structures Institute of Agriculture and Animal Science, institute of Tribhuvan University, Nepal International Association of Students in Agricultural and Related Sciences, Belgium-based international organisation Independent Academies Assured Services
Other Infrastructure as a service, a cloud computing service model Indian Audits and Accounts Service, an Indian Civil Service