Symfony is a popular, high-performance PHP framework used for building web applications. It provides a structure and reusable components that facilitate the rapid development of robust and scalable applications. Symfony streamlines routine tasks such as form creation, database interaction, and templating, enabling developers to focus on the business logic. Symfony's flexible and modular architecture allows developers to use only the components they need, thereby reducing unnecessary overhead. Symfony also adheres to MVC (Model-View-Controller) principles, promoting clean code organization and separation of concerns, which enhances maintainability and scalability.