Probably the most popular PHP framework right now. Laravel is powerful and elegant while still being easy to learn and use. Definitely worth giving a try!
Flight is a fast, simple, extensible micro framework for PHP which enables you to quickly and easily build RESTful web applications. Easy to use and to learn, simple yet powerful.
Yii is a high-performance PHP framework for developing Web 2.0 applications. Yii comes with rich features: MVC, DAO/ActiveRecord, I18N/L10N, caching, authentication and role-based access control, scaffolding, testing, etc.
Medoo is the lightest PHP database as it consists of only one file of 10,9kb. A great micro framework for small and simple applications.
Originally a fork of the Kohana framework, PHPixie is among my favorite new frameworks: MVC compliant, fast to learn, powerful. You should try it sometime soon!
Although being a bit old and reaching the end of its life, I definitely love CI which is a great MVC framework. I’ve used it countless times on many project and I never was disappointed.
Kohana is an open source, object oriented MVC web framework built using PHP5 by a team of volunteers that aims to be swift, secure, and small.
Created in 2005, Symfony is a very powerful MVC framework and is quite popular in the enterprise world. It was heavily inspired by other Web Application Frameworks such as Ruby On Rails, Django, and Spring. Symfony is probably one of the most complete PHP frameworks.
While some PHP frameworks are pretty complex and intense, Pop has been built with all experience levels in mind. Pop has a manageable learning curve to help beginners get their feet wet with a PHP framework, but also offers robust and powerful features for the more advanced PHP developer.
Phalcon is an open source, full stack framework for PHP 5 written as a C-extension, optimized for high performance. You don’t need to learn or use the C language, since the functionality is exposed as PHP classes ready for you to use. Phalcon also is loosely coupled, allowing you to use its objects as glue components based on the needs of your application.