The car was parked at Deltona Middle School on Enterprise Road.
The baby boy was accidentally left in the vehicle all day by a teacher at the school who was caring for the child, deputies said.
The sheriff’s office received a 911 call about the baby just before 4 p.m. Deputies said the infant was left in the back seat of an SUV that was in the front parking lot of the school.
A school resource officer got to the scene three minutes after the call, but the child was already dead, deputies said.
The sheriff’s office is still investigating the child’s death.
Dr. James Russell, the superintendent of Volusia County Schools, released a statement saying, "Our deepest sympathy goes out to the family and the Deltona Middle School community. This tragedy has broken the hearts of all of us in the school district. We will stand by the family with love and compassion."