Infrastructure as Code (IaC) with Terraform is an approach that involves managing and provisioning computing infrastructure through machine-readable definition files, rather than physical hardware configuration or interactive configuration tools. This technique leverages Terraform, an open-source tool by HashiCorp, to create, manage, and update infrastructure resources across a variety of service providers like AWS, Azure, and Kubernetes. IaC promotes DevOps practices such as version control, code review, and continuous integration and deployment.