The infant boy, who was born at just 24 weeks, died in hospital on Sunday.
His mother, 35-year-old Candice Rochelle Bobb, was fatally shot while in the back seat of a car on May 15, near John Garland Boulevard and Jamestown Crescent in suburban Rexdale, Ont.
Toronto police are still seeking information about the case. They have yet to arrest anyone or release any details about suspects.
Police said they believe Bobb, who lived in neighbouring Mississauga, Ont., was returning home from a basketball game when the car she was in was sprayed with bullets. Police suspect the vehicle was targeted, but that Bobb was likely not the intended victim.