The 407 Express Toll Route is the only toll highway in Ontario.  

The entrances to the 407 ETR are marked with large blue overhead signs and / or roadside signs.  Unlike a traditional toll highway, there are NO TOLL BOOTHS to stop at.    Overhead cameras are located at all on and off ramps and electronically record the vehicle’s license plate.  The toll is then calculated automatically, and a bill is sent to the registered owner of the vehicle.  There is no other way to pay 407 tolls.     All Canadian provinces and most American states have reciprocal agreements regarding collection of toll charges.    Unpaid tolls can cause problems with license plate renewals, etc.

Alternately, at no charge, you can use highways 401, 403, and the QEW ( Queen Elizabeth Way ) which parallel the 407 ETR route. 

Visit the 407 ETR website for more information.

Warning: Rental Cars and Highway 407

If you rent a car, you should probably avoid driving on Highway 407.

If you drive a rental car on the 407, the toll bill will be sent to the rental car company (the registered owner).  There is no other way to pay 407 tolls.     The rental company will then -- per the terms of the rental agreement -- charge an administration or processing fee, and bill the total amount to your credit card.  These fees can range from $10 to $60, and the fee is often much larger than the toll itself.  Unless the rental car company has specified (preferably in writing) an administrative fee for 407 tolls that you consider reasonable, it's best to avoid the highway altogether.

As commented above, you can use highways 401, 403, and the QEW ( Queen Elizabeth Way ) which parallel the 407 ETR route, at no charge