Well, it is yes and no.
Generically Qt is a bunch of C++ libraries, so it supports whatever C++ standard supports, including templates.
However, when it comes to Qt specific implementation it maybe different. Qt library classes, i.e., that derived from Q-OBJECT, can not be used with templates.
The reason behind is that Qt will generate moc_* for all Q-OBJECT derived classes, using template may mess up the moc code, due to limits of current Qt implementation.
If you use template in non Q-OBJECT classes, that should be fine.