Originally Posted by Backbencher

From the Canadian Border Services Agency Website:

Restrictions on temporary importing
If you buy, lease, rent, or borrow a vehicle while outside Canada, customs legislation does not allow you to bring it into Canada for your personal use, even temporarily, unless it meets all Transport Canada requirements and you pay the duties and federal taxes that apply. In the case of a one-way rental, you are allowed to drive the rented/leased vehicle to the authorized rental agency closest to your destination in Canada to drop it off.