Cut and paste from the Ontario Ministry of Transportation website:
Towing More Than One VehicleCars, passenger vans and SUVs are not permitted to tow more than one trailer or one vehicle. Motor homes, trucks, pickup trucks and truck campers are legally permitted to tow two trailers or a trailer and a motor vehicle behind a trailer. However, a three vehicle combination that is swaying excessively, is unstable or has reduced handling capabilities is subject to action by the police as an unsafe combination of vehicles under the Highway Traffic Act.
The maximum length of any combination of vehicles is 23 m (75' 6").