A pair of witnesses called police around 4:25 p.m. Saturday, after reporting that the two-year-old was screaming inside.
A fire crew arrived and was forced to smash the rear window to rescue the child.
The child appears to be fine, but has been transported to Sick Kids hospital as a precaution. The parents are with the child and will later be questioned.
It wasn't known how long the child has been left alone in the car for, but detectives are now investigating whether charges should be laid.