Janet Evans, who found her son Jamie hanging from a belt in his bedroom at the weekend, said he had been tormented by a gang of older boys.
The day before his death he came home from school with blood on his face and one of his eyebrows had been shaved off.
Mrs Evans, 53, said her shy son could not take the bullying any more.
"He was being constantly harassed because he was sensitive and quiet," she said.
"For a long time he was too frightened to tell us anything. But these bigger boys were waiting for him to take money from him to buy cannabis."
Mrs Evans, a retired shopkeeper, and her husband Tony are now trying to discover the full facts about the bullying.
Some of his friends have told the Evanses that a gang of older boys had been picking on Jamie, a keen sportsman, on his way home from school.
Police and education officials are investigating his death but do not believe the bullies were pupils at the school.
David Painter, the head teacher of the 1,200-pupil Maesteg Comprehensive, said: "The parents will be coming in to talk to us and we have got to find out what has happened."
A post-mortem examination was carried out yesterday at the Princess of Wales Hospital, Bridgend, and an inquest will be held.
A South Wales police spokesman said: "We will be speaking to Jamie's friends and other pupils at the school to try and find out what has happened."Reuse content