The incident happened at the intersection of Harrison Avenue and Heyward Street in the Williamsburg section around 5:45 p.m. Thursday.
Police say another boy was riding his tricycle between two parked cars when he went into the street. The delivery truck driver hit his brakes and swerved to avoid hitting the child.
In doing so, the driver struck and killed 5-year-old Joel Englender, whom he did not see.
The driver was not charged.