The Ministry of Transportation says Highway 401 has reopened between Mississauga Road and Winston Churchill heading westbound.
Ontario Provincial Police said that stretch of highway had closed after an early transport truck fire Tuesday morning.
OPP Sgt. Kerry Schmidt says the truck was completely consumed in flames around 1 a.m. and there was a significant diesel spill.
A full repaving of all westbound lanes was needed as a result.
Motorists were directed off the highway at Mississauga Road and were rerouted back on at Winston Churchill Boulevard.