| QMetaClassInfo | The QMetaClassInfo class provides additional information about a class. |
| QMetaEnum | The QMetaEnum class provides meta-data about an enumerator. |
| QMetaMethod | The QMetaMethod class provides meta-data about a member function. |
| QMetaObject | The QMetaObject class contains meta-information about Qt objects. |
| QMetaProperty | The QMetaProperty class provides meta-data about a property. |
| QMetaType | The QMetaType class manages named types in the meta-object system. |
| QObject | The QObject class is the base class of all Qt objects. |
| QObjectCleanupHandler | The QObjectCleanupHandler class watches the lifetime of multiple QObjects. |
| QPointer | The QPointer class is a template class that provides guarded pointers to QObjects. |
| QVariant | The QVariant class acts like a union for the most common Qt data types. |