Infrastructure as a Service (IaaS) is a cloud computing model where organizations rent computing resources—servers, storage, networking—from cloud providers rather than owning and maintaining physical hardware. Major IaaS providers include Amazon Web Services, Microsoft Azure, and Google Cloud. Organizations using IaaS can quickly scale resources up or down based on demand, pay only for what they use, and avoid capital costs and maintenance responsibilities of physical infrastructure. IaaS differs from PaaS (Platform as a Service, which adds development tools) and SaaS (Software as a Service, complete applications). Government organizations increasingly use IaaS for flexibility and cost efficiency, though security, privacy, and data residency requirements affect cloud strategy. Canadian government data may need to remain in Canadian data centres, limiting provider options. IaaS represents a fundamental shift from owning IT infrastructure to consuming it as a service.