Police said the student did not leave behind any suicide note.
His aunt, Ms Teresiah Mugure, said the boy had arrived a few hours earlier from his father's residence in Kiambu.
She said that after she forced the door open, she found the body dangling from the roof, behind the door.
A Form One student has committed suicide at Kasarani estate in Elburgon, Nakuru County.
Molo Sub-County Police Commander Isaac Odumbe said the body of Fredrick Kibugi was Wednesday evening found dangling from the roof of his room by his aunt.