Firefighters were called to a shed fire on Byron Avenue in the Campsall area of Doncaster at around 8:30pm on Thursday (27 October).
Crews worked quickly to put the fire out.
Once the fire was out, a body was found inside the shed, believed to be that of a 13 year old boy.
A joint police and fire service investigation into the cause of the fire found that it is thought to have started accidentally. Investigators will now collate their findings for the coroner.