There is parking but imagine trying to get out once the concert is over and prices for parking is insane, I recommend anyone to take either the Go Train (anyone from outside of Toronto, it stops right in front of the CNE grounds and you walk straight across the bridge to Molson or by TTC take the Bathurst street car (this will also take you to the CNE grounds from bathurst station)
SweeetSerialKiller liked a post in a topic by CokoKilos in Toronto, ON @ Molson Canadian Amphithere - June 3rd, 2015