Symfony is a PHP web application framework and a set of reusable PHP components/libraries. Developed by Sensio Labs
License: Open Source
Symfony is known for its flexibility and rich feature set, making it ideal for large-scale applications, while Zend Framework focuses on enterprise-level solutions with a strong emphasis on components and web services. Both frameworks offer robust support for MVC architecture and extensive community backing, but Symfony tends to have a steeper learning curve.