Highway 409 is an Ontario provincial 400-Series expressway that runs from the 401 in Toronto to Toronto Pearson International Airport, west of Highway 427, in Mississauga. Highway 409 is a short freeway used mainly a bypass for traffic approaching the airport from Highway 401 (westbound).

The portion of Highway 409 west of Highway 427 is owned and operated by the Greater Toronto Airport Authority , though it is still signed as Highway 409.

Interchanges from East to West

^† Exits are not numbered on Highway 409.