| Zend_Loader | Static methods for loading classes and files |
| Zend_Loader_Exception |
| Zend_Loader_Autoloader | Autoloader stack and namespace autoloader |
| Zend_Loader_Autoloader_Interface | Autoloader interface |
| Zend_Loader_Autoloader_Resource | Resource loader |
| Zend_Loader_PluginLoader | Generic plugin class loader |
| Zend_Loader_PluginLoader_Exception | Plugin class loader exceptions |
| Zend_Loader_PluginLoader_Interface | Plugin class loader interface |