Google Cloud SQL is a fully managed database service that allows users to run relational databases in the cloud. It supports popular database engines like MySQL, PostgreSQL, and SQL Server, making it easy for developers to set up, maintain, and scale their databases without worrying about the underlying infrastructure. With Google Cloud SQL, users benefit from automatic backups, high availability, and built-in security features. This service is designed to simplify database management, enabling businesses to focus on their applications while ensuring their data is secure and accessible.