Google Cloud IAM (Identity and Access Management) is a service that helps organizations manage who can access their resources in the Google Cloud Platform. It allows administrators to define roles and permissions, ensuring that users have the appropriate access to perform their tasks while maintaining security. With Google Cloud IAM, users can be assigned specific roles, such as viewer, editor, or owner, based on their job requirements. This granular control helps protect sensitive data and resources by limiting access to only those who need it, making it easier to comply with security policies and regulations.