Infrastructure-as-a-Service (IaaS) is a cloud computing model that provides virtualized computing resources over the internet. Instead of purchasing and managing physical servers, businesses can rent virtual machines, storage, and networks from a cloud provider. This allows for greater flexibility, scalability, and cost savings, as users only pay for what they use. With IaaS, companies can quickly deploy and manage their applications without the need for extensive hardware investments. Popular IaaS providers include Amazon Web Services, Microsoft Azure, and Google Cloud Platform. This model is particularly beneficial for startups and businesses looking to scale their operations efficiently.